I suppose I ought to come up with a short list of what I, as an entirely new random player with an okay enough record now to comment on stuff(maybe), have seen as weirdly imbalanced. By the game's standards, not my standards of balance, that is.
You see, complaining about intended imbalance is right out. Shotguns might be the better weapons overall in the game, but that seems known and intended(See the various differences in Angel difficulty commentary).
So, given a system of intended imbalance, only two types of things are worth commenting on. Those that would dominate the entire spectrum of builds, and those that would never be used. (And anything that almost always dominates, or almost never is used, etc.)
Since, if someone will always use something every time it appears, it kills the game being interesting(one optimal build completely dominates the game and everything else becomes challenge runs-except for those challenge runs that allow the optimal build, of course.), and if they never would use it, it's a waste of space.
For the former category, the only example of this seems to be Dragonslayer, and Dragonslayer is...a standard Roguelike conciet of the ultra-hidden weapon being best, so I can skip it on that grounds. People have talked way too much about it anyways, from what I saw skimming the forums before posting.
So, here's the stuff that struck me as bad enough to see little or no use, just from the on-paper. Obviously, I am bringing these up for discussion, not trying to just toss my opinion around. I've done some similar assessments on ToME forums, with suggestions people usually liked, so it's worth a try here, I think.
Talents:
-Survivalist.
Classic case of a win-more skill-if you're nulling damage to 1 constantly, nulling it to 0 isn't going to be that much different, and if you're not, the skill does very little. Allowing you to overheal on Medkits only matters if your inventory is full...and if it's full, you're either hoarding a whole lot of ammo, or have half a dozen to a dozen medkits, depending on the build. Or things you consider as valuable as Medkits.
If you're in the situation where this is optimal-you're taking a lot of 1 damage and have a ton of Medkits so you just want to use the ones on the floor instead of picking them up-you're in extremely good shape anyways. If you're not, the skill does nothing. And I question if the skill is actually better at saving you HP/Armor than a single level of Hellrunner(to say nothing of the fact that it seals off Dodgemaster-a strong tanking build with that on it would be very, very hard to kill.).
Oh, and if I read it correctly, Large Medkits heal you for 50% of your life or to 100%, whichever is better, with Survivalist. A heavy tank build, even on N!, only very rarely is going to lose 50%+ of its life in a single action(Or, rather, it can very easily do this, but you're likely to die if you let this happen commonly-with good play, it's very rare.), so it's more optimal to save Large Medkits until you actually need the heal than it is to overheal with them as a defensive buffer.
The first thought I have for this skill is 10-15% damage resistance, or 20-25% in a few areas(Maybe Plasma/Acid/Fire, since it's easy to imagine a survivalist type somehow living through large explosions. This is proper FPS/action movie thinking, right?). This makes it grant a unique tanking advantage, and makes it more likely that the first advantage(the nulling 1 damage to 0) will actually be relevant.
Of course, it's basically a blank slate as it is, so adding any advantage, or strengthening the ones that are there(Say, having it null damage randomly that is above 1, at a rate of (1/(N+1)) where N is the damage-so, null 1 50% of the time, null 2 33% of the time, etc.) would work too.
Juggler:
Not actually imbalanced per se, but, IIRC, I've seen discussions about how this ability is much better for the heavily spoiled player that digs through config files than it is for the average player.
Honestly, the answer seems simple to me. Make it two levels, make the first level grant N% speed to all equipment changes(weapon, armor, prepared item, etc.) and make swapping to the prepped weapon take 0.1 seconds(like it does now), and make the second grant N% more.
0.66/0.33 for swaps or 0.5/0.1 both seem reasonable to me. Depends on how good you want it to be. Being able to swap armor faster would make up somewhat for the loss in weapon flexibility, and it functions much more sensibly.
-Scavenger, Entrenchment
See above discussion. I'd be interested to see if anyone defends Entrenchment. Scavenger arguably doesn't belong anyways, on the grounds that anyone going for Assemblies will care about it anyways-so it effectively can function as a challenge run in and of its self, with a kind of long term achievement as the goal.
As I mentioned, Scavenger being able to mod all uniques once(Or even being able to mod them into basic assemblies) would increase the niche of the build-it would go from a rapid fire to a potential all-rounder. Still probably better at rapid fire than most things, though basic assemblies could be randomly funny. (Plasmatic Shrapnel Jackhammer.) And at least picking up a high end unique pistol(Like Cleric) would make them clearly the best user of it.
Entrenchment just seems like a case of needing more damage resistance. As mentioned, the reason that things like Malicious Blades work is because you're getting such good resistance off of it. Standing still is a pretty large downside, much like having to operate in melee is a downside for Berserker/Malicious Blades(well, Blades doesn't make you, but the skills leading up to it make it hard to avoid.).
-Gun Kata
I'm a little reluctant on this, because I have seen defense of it. I just can't entirely get why. The main upside seems to be the automatic reloads(0.1 shots after a dodge is nice, but SoG3 gives 0.4.), but with cutting out SoB, the damage potential is lower than other pistol builds even counting in the saved reload time, long term. You might be able to balance that out with specific setups, but the flipside is that you can balance out the requirement of reloading repeatedly with specific setups too(like just Bulking up your Pistols some.).
And the main time it's beneficial is the situation you least want to be in, again-in the open, being shot at long enough for both repeated dodges to be required and repeated reloads to be necessary.
This is less me saying the skill is useless, and more wondering what it does that, say, SoG3 and a few levels in Reloader wouldn't. And given its lack of SoG req, and the fact that SoG is very important for pistol builds, it seems like a late pickup at best...and late means that it's having to deal with iffy to dodge enemies like Mancubi. I dunno, it just seems a bit weak given how focused it is.
Weapons/Armor/etc.:
-Mjollnir
Haven't actually gotten this yet. Wiki claims it's a weapon that can only appear later than a Chainsaw, does less damage than a decently modded Combat Knife, and...that's it? Is the wiki missing some trait here like that it boomerangs when thrown? Even with that it might be questionable at 1-15 damage range. Regardless, if it doesn't boomerang, it probably should. :)
-Subtle Knife
3d5 is, again, kinda questionable, and for some reason the ability, despite being fairly similar to the Arena Master's Staff, takes MHP. I don't see a reason why. This is, at least, a bit better than a Combat Knife(...though it's oddly close to a heavily modded Combat Knife.), though, so it has some vague use for Malicious Blades builds. That ability doesn't really need to take MHP though, that I can see.
-Demolition Ammo
Another one I have to trust the Wiki on(There's only so fast I can get everything in the game.). It says, if I read it right, that it converts the damage of the weapon it's installed into to (Original Dice+2)d2 and makes it deal damage in a blast radius of 1.
I think the only times that actually nets higher damage are with a Combat Pistol and a Chaingun, and in both cases it's basically negligably better. Many times, that seems way worse. And radius blast normal shots can be self harming as well, making it a rather weirdly mediocre mod considering how good the other Master Assemblies are.
Considering that it takes four mods, wouldn't something more like (Original Dice+2)d(half original sides, rounded up) make more sense? It only impacts 10MM, and considering that a Firestorm, a Power and two Technical are involved, that seems more the pace of the investment involved.
Sure, you can make a really amazing 3d4 rad 1 Chaingun then, but how often are you going to want that over a Plasma Rifle with heavy mods? It's got some advantages and some disadvantages as well, it seems like. And if that's too good, you can always make it round down instead(which mostly makes it good for Combat Pistols and Chainguns, again, but at least a 3d3 Chaingun is worth mentioning.).
-Frag Shotgun
I'm not sure why there's a Unique Combat Shotgun that uses funny ammo, but it crunches enough of that funny ammo so that it's not more ammo efficient(A stack of shotgun shells is 30 and a Combat Shotgun eats one at a time, this eats four of 10MM, and they show up in 100 stacks. It's not even that much more efficient on a by-enemy-drop basis, since you get 140~ 10MM from a Commander and 30~ shells from a Sergeant), it doesn't do more damage, it hits the same cone, etc.
Oh, and it's 1.5s firing speed. For some mysterious reason. This seems like a good candidate for worst weapon in the game, and it's even unique so you can't mod it. At least you can make a Combat Shotgun into a Tactical, so it's better in every way, then. This weapon confuses me; I don't even know where to begin with it.
-Combat Translocator
Not actually a concept I dislike, but it consumes ten cells a shot(higher than a Plasma Rifle, two thirds that of a Tristar Blaster!) and randomly phases enemies.
The funny answer that comes to mind is to greatly lower the cells(to be honest, 1 would be okay) and have it function as a homing phase device when it hits enemies. Sending them to the stairs. Where you know where they are and can plan around that.
Of course, if you don't know where the stairs are, or are just trying to get through fast, spraying that around might be a bad idea. Then again, you can figure out where the stairs are pretty fast that way.
Alternatively, just give it an alt fire where you can shoot yourself with it. That might be too good, but it does take a turn to swap to...
-Bullet-Proof Vest
You know, I'm reluctant to list this one because the description its self implies that it's not expected to be worth much.
It's still not worth much, though. It's basically worse than a green armor to me, because I consider the main earlygame threats to not use bullets, so it's basically a worse green armor. And chances are, I'll be able to find a green armor.
So yeah.
It's not really that long of a list for me. There's some debate for some of it, too, surely.