Really good points OP, it doesn't reflect well on Larian at all and gives me concern going forward with the development of the game. I touched on similar things in another thread when I first read that quote about players wanting fireworks and damage. My initial issue with it is just how horribly misguided it sounds, it comes across as if Swen speaks for every player purely on the basis of their subjective data analysis. Did the thought seriously not enter their head that players aren't using buffs and debuts because of their horrible implementation?
As a veteran of the original BG/IWD games it took me some time to understand the new 5e spell mechanics; everything had changed so drastically I was initially confused why I could only cast 1 buff at a time and without fail the concentration was always interrupted, thereby making them a totally obsolete choice in battles. If players are trying this game having no experience of DnD then it's no wonder they aren't going to use buffs/debuffs because frankly the benefits are just not apparent. This in turn leads to spam casting the same offensive spells over and over again; combat becomes boring and repetitive...but glossy to look at.
Less style, more substance please Larian.
