What I think is the biggest problem with WoW nowadays is that there is no longevity.

In Wrath of the lich king for example (at least at the start), not only did you have to progress through old tier raids to catch up, but they also kept older dungeons and raids relevant by having daily and weekly quests that gave you Valor points that you could spend to buy relevant gear.

Now we have LFR

Now I'm not saying LFR is necessarily bad, but it does bypass 6months - 1 year - 2 years worth of content because the gear is better than what you'd get from previous raids and at the same time makes current content old news in the span of an afternoon, especially if you're only there to see the lore.

Likewise in every other aspect of the game, there are so many catchup mechanics in place for absolutely everything that you're up to speed with the game in maybe a week.

All of these catchup mechanics would've been great had there been stuff to do once you'd caught up, but there isn't.

WoD especially has been absolutely awful in terms of content outside of raiding, which again is trivialized by catchup mechanics, sure there are 4 different difficulties, but at the end of the day, it's the exact same content, with the exact same loot with a different number and color attached to it.