Just a couple thoughts regarding turn-based strategy games (including strategy RPGs).

1. Counter-attacks: Do you like it when units counter-attack when hit, or would you prefer it if they only attack on their turn? This is one thing I've noticed is common in these games. For example, here are the approaches some SRPGs take:
* Fire Emblem: A unit will always counter-attack with their equipped weapon if the original attacker is in range. (One thing of note regarding range: Bows can't hit in melee range. Spells can, however (as well as at range 2), and since spells are treated like weapons, it is possible to counter with them (except for staves)).
* Final Fantasy Tactics: Each character has a slot to equip a Counter ability. There's no default counter-attack (though there's an early counter ability that just counters with a regular attack).
* Disgaea: Each character gets a certain number of counter-attacks per round (and that number is 0 for some, like for spellcasters). Unlike the other games I listed, counter attacks can be countered, leading to counter chains. (Interestingly enough, in Disgaea 4 there's a way to get a long counter-attack chain between 2 invincible units where the damage grows exponentially and eventually overflows; this is the only game I'm aware of where the mechanics make it possible to overflow a 64-bit integer.)

2. Damage versus HP: When an attack does damage, how high is it, in general, in comparison to how much HP the target has? This change does have some consequences in terms of how the game plays out:
* When damage is high, battles don't last as long, obviously.
* Status effects (both positive and negative) tend to be more useful when damage is low; when damage is high, it's usually not worth bothering with them when the enemy won't live long anyway. (Of course, this assumes there are status effects the player can take advantage of; also, this factor affects negative effects more than positive effects, as positive effects can be applied when the enemies are still far away.)
* Healing is more useful when damage is low. Healing effects are useless unless you can heal enough for the character to survive an extra attack, and that can be hard when damage is high. In fact, in the extreme case, where every attack is a one hit kill (Disgaea 3's postgame, from what I hear), healing becomes useless (except for revive effects, which I'm pretty sure Disgaea 3 doesn't have).
* One could also factor in the influence of spike damage, for example, from criticals. When the game is balanced so that critical hits can one hit kill the target (think Fire Emblem here), combat becomes more random, and critical hits become more valuable.

So, any thoughts on this? What are your preferences regarding these mechanics?

I know this is one thing that annoyed me in Shining Force (Sega's early equivalent to Fire Emblem). Hitting an enemy always brought counter attacks, and that made aggressive strategies a little harder because getting a warrior too far from a healer to get quick snipe kills (or Isolating out one enemy quickly with a glass cannon) was very detrimental. It meant that ganging up on a strong target was virtually useless because they could still readily decimate your weaker defense characters.

As far as HP goes, I'm ok with high damage. Healing to me is useless in low damage games. Why heal if they're only chipping my HP? But in high damage games surviving that one extra round can mean the difference between victory and reloading. I like some spike damage, after all random is the name of the game. If you already know the exact outcome, what's the fun in playing? But it shouldn't be so often that it get's exceptionally frustrating. Sometimes is cool. If a character has an unblockable super attack that can one shot characters and you have to kill him before he can use it too many times, that's just unreasonable IMO.

I'd rather not have counters, since it ends up being a punishment for, well, fighting, and there are usually way more enemies than player characters, so the player tends to be on the receiving end a whole lot more. May be a special ability, so you may have a small number of enemy types that can counter in a limited manner, usually once per round, maybe twice for the more skilled, while most still won't, and player characters will be able to gain the same ability in that case if the player wishes, possibly training it for more counters per round and turning it into an advantage overall.
At the same time, it can work if you do have counters as well, but depends on implementation. Much better if damage is low, and I'd much, MUCH rather have low damage and long battles under any circumstances anyway.
An interesting implementation is in Age of Wonders, where units counter in melee but they use their next turn moves to do so, so it becomes an important tactical aspect, wearing down either more powerful or just very fast enemies by having them counter units that are either expendable or can take the damage so they won't be able to freely choose the target, or even act at all, the next round. And, of course, need to watch it so the enemy doesn't do that to your units.

Actually, when there are more enemies than player characters, enemies will be attacking player characters, and therefore player characters will get more chances to counter.

One thing that can happen, for example in Fire Emblem, is that a payer unit with high defense or evasion gets attacked by a whole bunch of enemy units, counterattacks each one, and gets a whole bunch of kills in one turn (albeit at the expense of weapon durability if we're talking about Fire Emblem).

Final Fantasy Tactics's implementation is different, as the "counters" can be things like countering enemy spells with the same spell or even getting a free turn when reduced to critical HP (which is part of the exploit that makes it possible to deny enemies the chance to ever act again). Then again, there are so many ways to break FFT, and the game even hands you a game-breaking character after a certain mandatory story mission (in other words, you will get him unless you explicitly turn down his offer to join).

By the way, one other consequence of damage amounts: If damage amounts are low, boosting the player's defense may be hard to justify (particularly if the player has access to healing), but if damage amounts are high, a defensive ability can mean the difference between surviving an attack and getting killed.

I don't like that Age of Wonders example where characters are forced to use their next turn outside of control; I think it might take too much control away from the player.

In low damage games, there's still the danger of being worn down over a series of battles. In fact, one thing I often see with some non-tactical RPGs is that you get into situations where individual battles don't hurt much, but over the course of a long dungeon, you need to heal (perhaps between battles) or you'll run out of HP and game over. (There's also the option of retreating, resting at the inn, and trying again.) In an SRPG, this can happen within the course of one map, though I note that healing-over-time options are more viable in low damage games.

You mention the case of a character with an unblockable OHKO attack, but what if *everyone* had an unblockable OHKO attack? Incidentally, from what I hand, Disgaea 3's postgame combat is like that, except that the attacks aren't unblockable (high SPD can let you evade them), and the whole idea that you want to avoid "End Turn" as much as possible in item worlds is magnified here. (I note that, in the Disgaea series, your humanoid can throw other units to cross long distances in a single turn, and there's also the whole Geo Symbol/Panel thing going on; I note that, in the Item World, each map is randomly generated and there's a square that, if one of your units can reach, will take you to the next level without having to kill every enemy.)

I very much enjoy that feature in warhammer 40k armageddon, every attack will invoke a retalliation if possible.
range and weapon types are the determination if a retalliation will follow. So artillery will never get a retalliation with their artillery weapon but if equiped with additional bolters those will fire back. melee infantry will never retalliate on a ranged weapon attack even from a range of 1/0 but will retalliate if attacked with a melee weapon

this effectively means that no one in their right minds will use mere soldiers to attack tanks or other well armored well equipped unit types since most top tier units will carry up to 3 different weapon systems of equal terror inducing proposition and different range sizes.

Another turn based strategy game that uses this card quite well is order of battle, it is only natural for units to retalliate when attacked or better said damage an attacker when under attack and if possible

Damage should always be a fixed range with health having nothing to do with this factor in most strategy games i play

ofcourse some fantasy rpg's work different, sometimes with percentage damage calculations but even then i prefer my damages in fixed ranges for standard weapon actions, plussed with criticals for weapontypes that have the ability to do a lot of damage with a higher skill ability and for spells , well with magic anything goes of course

How about having damage calculated different ways for different attacks?

Here are some interesting cases:
* Phantom Brave: For every stat (except SP, which isn't handled the same way as in the other Nippon Ichi games), there's some skill that uses it for damage.
* Fell Seal: Arbiter's Mark apparently has one skill that does damage based off the attacker's defense. There's also the Gambler class.
* Final Fantasy Tactics Advance has the Blue Mage job, which continues the tradition of having strange mechanics: Metra Magic swaps the target's HP and MP, LV? S-Flare works on every target on the battlefield whose levels are congruent modulo 10 to the caster's (from what I can tell from a description online), and White Wind is a healing ability whose healing amount is equal to the caster's current HP.
* Speaking of strange mechanics, Final Fantasy Tactics has the Calculator/Arithmancer job. (Same job, different translations.) Instead of their spells targeting an area of the battlefield, they instead target everything whose stat is a multiple of a certain value, as selected at cast time. (With that said, the fact that Math Skill isn't subject to any sort of range or locality limitations is part of the reason it's so powerful and game-breaking.)

(I have encountered this sort of thing in many non-tactical JRPGs as well, including early SaGa games and some Final Fantasy games (with Final Fantasy 5 being a good example of this, particularly since it's the game that introduced Blue Magic).) What about spells like the Gravity spells from some Final Fantasy games, or Mass Distortion from early Might and Magic, which differ from other attacks in that they take away a percentage of current health?

Well i love the idea of something wicked or only applicable to a specific situation as much as anyone else, so long the creator does not forget that going all out does not have to mean everything considered normal will be disbanded or provides enough imagery to help with envisioning how fights in his world will work out, e.g. we all know how anime ninja fights can go then i say god bless you

still i'm not sure if singular, one person at a time, fits the description of tbs in any meaningfull way but that is something else entirely different. I belief to a lot of people it just indicates turn based fighting in whatever way possible

1. I prefer counters only working on misses, not on hits.
2. The higher the damage/HP ratio, the better. I like games where characters can be killed with a single wound, as in real life.

Counter attacks:
I'm generally fine with a variety of counter-attack styles, so long as the game is properly designed such that you never *don't* want to counter attack. (This is often true of criticals, too.) Too many games in the genre and related reward you for making battles take longer ("gotta keep trying to steal until I get it!" "I *need* character B to get the killing blow!" "I need to keep fighting to grind out points in my stats...") One of the monster classes has an attack off of SPD too.

As a note, I often like Fell Seal's counters -- many of them are self-boosts or evades or return-a-debuffs rather than damage retaliates.

On the other hand, I don't like there being too much of an incentive to finish a fight quickly. If we take a baseline (common in non-tactical RPGs) where you get the same rewards regardless of the time the fight takes, that already favors winning the battle quickly; if there's an extra reward for, say, winning the battle in one turn, that favors it too much, and puts defensive strategies at a disadvantage.

Related, I find the following combination of mechanics to be rather silly:
* A character who is dead at the end of combat is permanently penalized in some way; for example, the character might be deleted from the roster, dead forever.
* It is possible to revive a character in the middle of battle.

By the way, it's possible to have situations where you might not want to counter-attack that don't involve the game rewarding counter-attacking. For example:
* The enemy has a nasty attack that it only uses at low HP, and you don't want the enemy to use that attack. (This also applies to passive and reaction abilities that only trigger at low HP.)
* Your counter-attack will actually benefit the enemy in some way. (For example, maybe you have a weapon that heals instead of doing damage.) Or, you're deliberately attacking an ally with such a weapon, and the counter-attack would hurt the healer as a result. (By the way, when I get around to Fell Seal, I am *so* going to get the healing staff that apparently exists and play around with it; I might even try modding in a gun with that effect and see how that feels.)
* The counter-attack uses some resource; Fire Emblem is a good example.
* The counter-attack will award you XP, and you don't want the XP, as it would give you a level up that, for whatever reason, is undesirable.
* The counter-attack's animation is too long, so triggering it will actually make the battle take longer in real time.
* There's a bug in the game that is triggered by the counter-attack in the right circumstances, and the effects of the bug are not favorable. (Of course, the developers should really fix the bug or not include it in the first place here.)

By the way, when it comes to Fell Seal, I still haven't decided whether, when I'm ready to play it (which will likely be after my Final Fantasy 5 playthrough), which of these two options I should take:
* Play through the game once without the DLC.
* Buy the DLC, and do my first playthrough with the DLC installed.

(By the way, Fell Seal has good music, judging from videos and a soundtrack sampler (which seems to be called an "EP") I found, so I might get it from bandcamp.)

Here's all of it. *shudder*
No kidding. And with me playing full defense, see something like that and... no way!
... Unless perhaps there's a defensive reward for being offensive that beats what you obtain by being defensive. There was a little browser game I played, Empires of Arkeia, where the rewards were for speed, exp was granted according to how fast you won, so the best strategy wasn't to do the rock-paper-scissors thing and try to counter enemy units with the most appropriate ones of yours and push the wave back but send riders on empty / poorly defended lanes to damage the enemy stronghold as fast as possible, leaving yourself open to the enemies, then when you charged a wave because of the damage dealt, use it to create a full line of engineers, which repaired a large chunk of damage right away.