There's been this mounting feeling for the past couple of expansions that more and more elements of the game feel so ephemeral. When you get to the point where it's so granular that they have it for one specific patch cycle (corruptions in 8.3) that's really pushing it. This has definitely colored my perception of the game as a whole and I am no longer able to really feel as invested or attached in anything the same way that I used to, because I know it's just going to be discarded for something else before long.
Ultimately I don't think the whole design philosophy of herding the playerbase into this ultra narrow treadmill of disposable "current content" at the expense of everything else in the game is good. It's probably a huge part of what drives the plunge in subscriptions inbetween launches. Other MMOs like ESO don't seem to have this kind of problem because they're not designed around that style of progression, and that has made WoW's approach seem all the more strange to me in hindsight. They spend so much time and resources on designing content that's only going to be relevant within a fairly limited time frame, and then they go out of their way to make you not want to care about it any more.