There will be people will literally complain about anything, because they are looking for reasons to complain. You have to be able to tell whether people are doing this because they are pessimistic or even, dare I say it, toxic, or whether there are genuine problems with the game. Eventually it reaches a point at which it's pretty clear, but usually by then it's too late to fix entirely until the next expansion (which may be why we see "good expansion, bad expansion" cycles, ironically).
Personally I think 8.3 is helping BFA tremendously, but it won't fix BFA's core problems. Unfortunately it's too little too late, so the game is going to suffer a bit until the next expansion. I've just come to accept that, and I am hoping Shadowlands will do better.
So far, Blizzard is taking the startling view that they've made mistakes and are trying to improve the game by breathing life back into it, instead of pushing grindy content they hope will keep people subscribed or... whatever the hell their goal is.
But I am digressing. The point is that there are always going to be people who are always complaining about anything and everything they can. This is just part of our culture now, it's definitely involving more than just this game. Classic, ironically, didn't help this because the community is divided even further. Any community that is around for more than a couple years will get this way, and trying to appease these kinds of people usually an effort in futility to begin with. Better to just try and make the game better for people who will enjoy it, instead of trying to please people who will complain about literally anything.