I couldn't care less about 'balance' in this game. I'm not competing with anyone and I don't know much about D&D so if I happen to stumble on an overpowered build, cool!

Back when BG1 and 2 were new there were overpowered classes that made the game easier and that was the case in any game out there that gave you any sort of freedom of choice. In a game of dice rolls, any advantage is just that, and there is almost always going to be an optimal avenue to an advantage. The only reason it wasn't a big deal back then was because there weren't 1500 videos on youtube telling you the most optimal way to play the game.

I guess if just exploiting the best builds and then complaining the game isn't fun is your jam, have at it.