Collect Mounts/Battle Pets/Achievements/Toys? Thats what I plan on doing anyway.
PvP? Level alts? Professions? Make gold? Plenty to do
Mounts: Got all the ones I like.
Battle Pets: If I get the urge to play Pokemon, I play Pokemon.
Achievements: Never cared for them, got all the ones that reward stuff I like, wasting time accumulating points to compare with others on how much time you have wasted accumulating points never appealed to me.
Toys: Meh.
PvP: If I wanted to PvP I would play a PvP game, I never cared for the PvP in WoW because it's so horrifically imbalanced, elitists will try and claim that skill > gear but it's nonsense unless your victim has learning difficulties, and wheres the skill in that?
Level alts: Nothing to do after completing the game, play it all over again. I think I will wait a bit before brining one of my alts up.
Professions/Make gold: Why? Apart from repairs I have no costs, the are hardly any enchants, I need no gems, and my profession crafts are time gated.
Plenty to do: Sadly not, every expansion they seem to add more to the game however they make less actual game, in TBC and WotLK I was completing quests for weeks after hitting max level, there were loads. This time I am done (except for legendary ofc).
At the moment I am basically logging on just to see if anybody want's to face roll 5m heroics for the hell of it, and sending my followers on missions. can't wait for LFR to come back