Title says it all. After extensively save-scumming low-level unique item chests (original campaign act 2, levels 8-10), the vast majority of melee weapons are exotic.

Estimated chance:
-35% double-bladed exotic.
-25% other exotic (kama, katana, kukri)
-15% ranged, heavily skewed in favor of crossbows (the ruby fear crossbow and the obtuse orc-hunting crossbow). I found the Elven Court Bow (+3 accuracy and mighty) several times and the Eaglebow (garbage) once.
-25% chance for any of these, most common to least common (legion mace, One of Many morningstar, Soulscythe, keen dagger, Hammer of Justice, and the bard-specific fencing sword)

This makes no sense at all. As far as I know, there's no character that starts with exotic weapon proficiency, yet the drops are heavily rigged in favor of exotics.

In particular, I have never found a unique regular sword. Can anyone confirm if they were left out of the item list for those chests by mistake and send the item name or item ID so I can add it through the console?

If you could tell the exact container / location you were trying we could have a look at it in the toolset to see what it does. Also your class(es), level, and weapon focus feat(s). In the OC the loot depends on the opener, not the chapter in the campaign. By your description of the loots it sound like you are a monk, wizard or druid with no weapon focus...?

Okay, I'll try here, since the title is just close enough to my problem.

So, I've downloaded NWN Diamond earlier through winter sale here on GOG. I know I've played the official campaign like 20 times before, but for some reason, I wanted to try again. I feel this is becoming a sort of a ritual, but whatever :)

I know the OC almost by heart now, and I knew something is not right, playing through the first chapter. Also, I know which bosses and which chests leave a unique item drop, so I save before defeating/opening, just to see what comes with the remains. So far, NO UNIQUE WEAPONS OR UNIQUE ARMOR WERE FOUND (sorry for the capslock).

I'm playing a druid, currently lvl7, normal difficulty, weapon focus on scimitar. Now, I know that there is scaling in the game, drops equivalent to the player level and somewhat to weapon focus feat, but to this point, I've found only some cloaks, darts and gloves. The best I've got so far is scimitar +1 and some light armor +1. I mean, I've loaded over and over again, boss chests were giving me regular sickles and spears.

Is this supposed to be expected or is there a glitch?

I did some more looking around. There are six level ranges in the OC's loot system. And yes, there are many many "boss" containers in Chapter 1, and when your level is not high enough, you will be finding lots of regular weapons and armor in them.

Character Hit dice
1-5 ... regular crap
6-8 ... +1 items
9-10 ... first named unique items (allegedly)
11-13
14-16
17+

Many thanks. I'll see what I find later as I level up.

Couldn't be farther from the truth. Elf Cleric/Wizard/Arcane Archer.

I've also been finding a crapload of staves (the stupidest weapon in the entire game, 2-handed with 1d6 damage), exotic weapons, and I also get bard-specific items.

I have yet to get any unique longbow other than the Elven Court bow. If any of you can confirm any other longbows that should be in the list, post them here.

OK, I am getting more certain you have OCD.

I have played the original campaign 4 or 5 times. I have never had any issues finding the type of weapons that I set focus for. Martial Weapons are my preferred. Usually Greatswords.

I find +1 versions early on, then named and +2, on up the ladder.

Looks like you completely misunderstood the issue. In particular, it's related to guaranteed unique item chests (usually boss/miniboss chests that give a "random" unique item that should supposedly be based on the recipient's class.

These have nothing to do with +1/+2 upgraded generic items. Uniques have their own set of built-in affixes and (usually) no designated enhancement level.

In particular my build is a cleric-based arcane archer, intended to use longswords and longbows. From unique item chests:
-I have yet to find a unique short sword
-I have only found 1 unique longsword (Cold Iron Blade)
-most ranged weapons are crossbow or throwing
-I have found 2 different unique shortbow types (Eaglebow and Oathbow) although those are both bad
-The only unique longbow I ever received is the Elven Court Bow
-All other item types are plentiful, particularly exotic weapons and staves(the worst weapon in D&D, 1d6 damage and large).

The only logical conclusion is that the loot system (at least with weapons) is specifically rigged against the player.

-Someone claimed in an earlier post that it's based on class and specialization, in which case there shouldn't any bard-specific items or exotic weapons for a cleric.
-No idea if the random unique items consider racial proficiencies.
-If the random unique items are supposed to observe your class and specializations, then I should be receiving plenty of longbows and shortbows after taking my first level of Arcane Archer.
-Even in the early levels (Cleric only) I would routinely get bard-specific items and sorc/wizard specific staves.

Crooked, crooked, crooked!

Anyway, what's the longbow reward supposed to be in the 11-13 level bracket? I'm going to add it through dm_spawnitem. Remember that this discussion is a question: help out, discuss constructively, or get out.

Staves are Wizard Weapons, one of your classes is Wizard. Arcane Archer is an expansion class, which I doubt original campaign was ever updated to support. So only Cleric and Wizard likely affect class based distribution. IIRC Elven court bow is just about the best bow drop you get in that range. No, the logical conclusion, is that you are leaping to faulty conclusions, based on insufficient understanding, just like you did with your "Rigged D20" posting.

You had someone offer to check the exact chest you have a "problem" with. Why not follow up on that?

OK, I got one of the two base professions. The "class to use" is determined by weighted probability. For example, a Cleric/Wiz/AA 8/1/9, will find "cleric stuff" on 8-in-18 odds, and "wizard stuff" 10-in-18. The prestige class lumps in with whichever class is listed directly above it.

Most loot is generic. These class rules apply only to certain containers, which is why I said it would be helpful if you could post your class and level, and the location of this particular container.

Without better input from you I can only suggest that you'd want a "feat" chest, which checks weapon focus and level instead, if you want a decent shot at finding a bow. Wizards and clerics seldom find good martial weapons. The only feat chests I can remember are in chapter 1, beside the yuan ti and the devourer, but I guess there are others later.