Our good friend Peratryn at Blizzard has fixed the mount count issue on the battle.net site, allowing our mount rankings
to accurately reflect the in-game mount counts once again. Should you find any mounts are still missing then please post up on the official forums
PERATRYN: I have a fix for this going out later today that I think brings us very very close to accurate counts on the mounts tab. Please just post about any issues with your mount number not matching in game and we can try to take a look over the next few weeks. If you know which mounts are listed incorrectly that helps even more.
The removal of retired mounts from the collection was due to an incorrect solution to the faction-mount problem. I'm sorry it took so long to fix.