A blue poster stated a few changes with 4.0.3 mount drops, including Invincible and Mimiron's Heads would be set to a much lower droprate than their currently guaranteed droprate when done on hardmode. The post then went on to explain that the ZG pets and mounts would also be removed, but wouldn't be done until the Shattering in 4.0.3A (presumed to be roughly 1 week prior to the release of Cataclysm).
With the ZG changes being in mind, is Blizzard considering not lowering droprates on Invincible/Mimi's head until 4.0.3A? I am 3rd in line for Invincible and the only way I am guaranteed the mount is if the droprate change doesn't occur until 4.0.3A, or 4.0.3 doesn't launch until after the 23rd (which I doubt at this point).
I would really love some clarification on this! It would kinda suck to not get an Invincible, when our guild has been farming the mounts for so long (US 21st LK kill and all).