I feel that in order to keep some form of prestige for the heroic / hardcore raiding crowd, Blizzard should return to the policy of removing raid achievement mounts each new tier of raiding is released.
Why should they do this?
1) To keep rare mounts and exclusive content more prestigious
2) To distinguish good players from the rest of the riff raff
3) To give incentive to guilds to participate more in the higher end raiding
4) Most importantly, with the implementation of the BMAH, these mounts would still be available to the masses
The days of gear meaning something are long gone. Any scrub can "look" like they are well geared with the implementation of LFR. This is fine. But if rare mounts are removed each new tier, you will know a player is good by the mount they sport, rather than by the gear they acquire.