WoW core gameplay was at its peak with WotLK, as was the sub count.
Cata post-merger team drastically changed core gameplay ontop of cut and reused content. It's almost like the game was remade by a new dev team, for new players, inspite of the current playerbase.
Every expansion after Cata had (mostly) failed attempts to change core-gameplay further away from its roots. A proverbial "It's my turn."
And then you get bullshit moves to back-seat monitor their own forums with Real-ID, Facebook, and Twitter integration. Then they have the nerve to tell people to post on Twitter to reach a blue poster even if the official forum is having no issues? Because they want Twitter to moderate posts for them. A safe-place for devs to shit-talk their own customers.
Gameplay no longer drives players, just content. Legion tried to inflate content with RNG and time-gates, it lasted a couple months at best. There's no reason to "experience the game all over again" by leveling a character from 1-100 because it means further time-gating yourself.
The shallow gameplay can't keep people justifying a sub fee, except maybe the FotM rerollers who have no self-worth. People might resub for a new patch or holiday event (and now they're adding micro holidays, coincidence?).
The post-merger devs are narcissistic jokes who constantly shelter themselves in the safe place that is Twitter. Any attempt to criticize them results in summoning the hoard of "culture" addicts who care nothing for the game and only the perceived pseudo-"family".
And for the record, I haven't payed a sub fee since Tokens were introduced and I don't plan on it until the post-dev team gets fired or they back-peddle all the trash class-revamp shit since Cata.