Before the changes we usually didn't see locks in the top 1000, which is pretty bad by any standard. Some specs also got nerfed, and the net result was warlocks being relatively better off, and before that it wasn't exactly wrong to say that warlocks were pretty / very bad.
Well, sometimes it just seems that way, mostly because of the "warlocks are perfectly fine for mythic+", etc. I guess I'm reading that as "nothing is wrong with warlocks" and not "warlocks can do well in mythic+ unless pushing for top world ranks". It is hard to tell sometimes, but I guess that is part of reading forum posts.