They dont care about the feedback. They care about how often we login and how much time we spend playing each time. So they design the game to maximize that. Everything other is moot for them. They dont change anything unless things they care about change.
Fun fact: Blizzard is couple of builds ahead of what public is testing on new expansions so it is almost pointless to give then any feedback other than bugs because they are not interested in change. They know best
EDIT: when i said "devs" i mean in broad terms, not blizz devs.