The overpowered classes are hand crossbow and shortbow, both of which have unique characteristics that make them good against basically everything. this is not really the case for ranged characters, for obvious wall-related reasons. it ends up being a lot more difficult to really make good melee characters, and you do run the risk of them dying quite a bit. dagger without multi-hit is terrible, for example. The problem with melee classes is that you have to build both survivability and damage, and a lot of the melee kits need offensive stats in order to be any good at all. that being said, I did just use one to kill one of the final bosses with 1AP so. the third one is dagger, which is very good but also basically just spams throwing dagger all the time, so they're kind of not melee in a sense. There are like three melee classes that are any good at all, and two of them are really late unlocks (greataxe/greatsword). Speaking of weapon classes, my only real issue with the game currently is that I think some of the weapon classes are a bit over/underpowered, and I'll toss this in a spoiler just in case you want to go through it without being a metalord:
not really a huge deal, but it's worth getting new weapon classes when you can. The unlocks are reasonable to get for the most part (I'm at about 70% on both unlock tracks), but there's a little bit of weirdness regarding when you unlock certain things - some weapons are locked behind certain upgrades you wouldn't necessarily expect them to be, for example. (just completed my first run successfully a few minutes ago.) the high-level idea of the game as a turn-based strategy roguelike is both novel and really well-executed, and the game does a really good job of making you constantly feel like you're close to getting a poor rating/losing - and the poor ratings generally snowball into losing, because you get fewer rewards, and so on. So I've put about 18 hours into this over the past few days, and it's honestly a really good game, even in early access.