There were questions rising concerning Mimiron’s head and new Achievement for obtaining one that’s being implemented in the game(feat of strength). As only mount based Feats of Strength are the rare drop mounts, while Mimi’s head is a guaranteed drop.
Anyway, no need to fear … Mimi’s head will stay in game, for now at least.
Quote from: Bornakk
There are no plans to remove this mount in patch 3.3. Good luck on more Yogg+0 attempts!
(Source)
