Bring back FOMO Content, but not FOMO cosmetics
For example:
FOMO Content is the MoP and WoD legendary Cloak and Ring questlines
FOMO Cosmetics are the Challenge Mode appearances, AOTC Mounts, T3 Gear (Still Attainable through BMAH)
Players should be able to experience all the content that has ever happened in the game.
But, players who did the same content as current and got time-gated cosmetics as rewards should not lose the prestige associated with those rewards.