I've just reached the red mines (2nd area). Here is my party's stats:

L4 Half-Orc Barbarian: 18 END, 68 HP
L3 Human Paladin: 14 END, 27 HP
L3 Human Archer: 16 END, 27 HP
L5 Dwarf Robber: 20 END, 65 HP
L4 Gnome Cleric: 17 END, 28 HP
L3 Elf Sorcerer: 15 END, 12 HP

How badly did I mess up by not rerolling so that the sorcerer has 20 END (or whatever elf max is)? What about the others? I made sure their primary stat is 20, but as you can see for the rest I felt rolling 14+ was acceptable (I was focused on accuracy.

The above is my primary question, but I have a couple of other questions since there's so little info about this game:

b) I didn't realize the robber had Luck as prime statistic (the GameFAQs walkthrough didn't mention it, I later saw it in the official manual). I left it at 17. Is that another grave mistake?

c) In Vertigo (starting city), merely opening doors would randomly knock out a character. What's the deal with that? Is this some nonsense about hidden traps? In normal city passages?

d) Is there anywhere that provides a comprehensive summary of the story before MM4? I read Wikipedia and the fandom wiki, so I have some clue what's going on, but they were just 1 paragraph.

You really should mention which game you're talking about. Assuming you're talking about World of Xeen (since you mention Vertigo):

1. There are *plenty* of opportunities to raise your stats. In the mines, for example, there are barrels that will give the character +2 to a stat (save first so you can reload if it's not the stat you want for that character, and you'll also learn that each color corresponds to a specific stat (the colors appear only as text, so no color-blindness issues here)). Later on, there are even bigger bonuses available, including one dungeon that has, I believer, 8 doses of +40 Endurance, so a measly 20 isn't going to matter in the long run.

There's also diminishing returns; after a certain point, you need *25* points (IIRC) of a stat to increase the bonus one more point; that's bigger than the difference between the lowest and highest possible starting rolls.

(Note: Some stat bonus events are bugged and will get used up even if you cancel out of them, so save *before* checking the first time.)

2. Again, given all the opportunities to boost stats, a low starting Luck is not an issue. The main thing with Luck is that it boosts your resists, but will only do so if the resist is at least 1, so distribute your resist boosts (both from equipment and from the few resist boost events that exist) accordingly. (Also, in the long run, I note that Energy is the most important resist.)

https://www.angelfire.com/ma3/neatpics/mmhistory.html

Note that those early (Ho)MM games didn't have super deep stories. It only started becoming complex from HoMM2/MM6 onwards.

Thanks! It was indeed MM4. Glad I don't have to restart. Some more questions if you don't mind?

1) Who would be good candidates to prioritize for Speed upgrades? Is this a case where I'll never be able to act first in combat if I try to spread Speed around due to everyone having mediocre Speed ? Should I focus on 1-2 people having high Speed (like Cleric so he can heal early people on the verge of dying before enemies get a hit in, Barb/Sorcerer to nuke the biggest threat ASAP)?

2) The manual says Luck affects trap avoidance. But the GameFAQs walkthrough doesn't mention this. Is it just used to unlock the class and then has no unique effect on the class's gameplay? Basically do I make sure my Robber has high Luck and have her search/open everything? Or just aim for reasonable luck on everyone to help with resists in combat?

3) Does Might have any effect on bow/sling damage? Or is my Paladin doing practically the same damage as Sorcerer with a Sling?

4) Will the game become trivially easy anyway (even on Warrior difficulty) later on, so I shouldn't overthink any of this? Or am I right in planning properly.

Yes. You will have a few tough boss fights, but otherwise it becomes a walk in the park at a stage. You don't need to overplan, any "good" combination will work.

1) I usually give them to the barbarian but other options work too.

3) Only dexterity affects ranged weapons.

For Speed, you want to have as many characters as possible that can move before enemies get an action. Ideally, you will have enough fast damage-dealers that the enemy dies before their action in the round comes, at which point that enemy cannot hurt you. That means you need at least one character whose speed exceeds the enemy, so yes, spreading speed around is probably a bad choice.

Making the cleric fast may not be that important. Action order is deterministic, so an extremely slow cleric can get the last move of every round, allowing spells before the next round starts and the enemies move again.