I don't really buy the "you don't have to use it" argument. You can apply that to everything. A specific subclass is way too strong? You don't have to use it. Some magic item completely breaks the game? You don't have to use it.
Feels like a blanket excuse for any balance issue...
I want to say that this is literally the only cRPG I've observed within the past 4 years that I've become familiar with the genre where this specific defense of 'Don't like overpowered thing? Don't use it!' is brought up so much. I've only ever seen this argument for jRPGs beforehand. It's almost like there's something inherently wrong with the balance in this game for it to be the go to argument for dismissing criticism.
There is a gigantic contextual difference between a spell that's overpowered when used in a very specific way, and something literally every character can do from level 1 that's outright stressed by the environmental design. There isn't a tutorial on using cloudkill, but there is one for height/backstab advantage, and there are conveniently placed ledges and barrels everywhere in comparison.