I used to read and hear that all the time in Justice League's heyday, but perhaps it's not the best example for the point I'm trying to make.
This is - at worst - Bruce Timm designs that have been brought a bit further to life by being ballooned into CG. If this were 2D hand-drawn identical to JLU and all the recent films, there'd be no problem because we know the strengths of these things have always been in the stories and direction and so on. But when they try to take the animation a bit further, suddenly the fans are entitled to way more and it's not good enough for them to even be "on board"?