Gladiator mounts should be purchasable. Not the current mount or even the one before that, but any others should be fair game.
I am sure plenty of people are about to unload on me for even stating this but just listen to my point first.
There are hardcore PVP players and there are hardcore PVE players. Both groups have their own mounts to display their skill level. The difference is that a PVP player w/ no raid skills can pug old raids and dungeons for meta-achievement mounts; the exceptions of Kor'kron War Wolf and the mounts that Blizz removed from the game (the original ZA bear, plague & black drake, and horses from TotGC - all of these Blizz later stated they regretted removing them.) Many of these meta-achievement mounts can be soloed or completed w a small group of inexperienced players. Even the Ashes of Al'ar can now be obtained by almost any decent geared PVE or PVP player through soloing.
But there is no way that the PVP mounts can ever go to a PVEer or anyone who isn't hardcore PVP. The plague drake and the black drake have even popped up on the BMAH but no gladiator mount has.
What I would like to see is that older gladiator mounts become purchasable for like 25k conquest points each, if not more. Doing this would build interest in pvp for those who did not have it before and give an added reward to those who pvp all the time but may not have certain mounts. By blocking off the previous 2-3 gladiator mounts, it allows the mount to remain a status of skill for about the length that pve meta-mount represents the current skill level.
No one is clinging to their Reins of the Bloodbathed Frostbrood Vanquisher that they received from Glory of the Icecrown Raider, their Red Proto-Drake from Wrath Dungeon Hero, or their Rusted Proto-Drake they got from Glory of the Ulduar Raider as a testament of their PVE skill, why should Gladiator mounts from the same era be any different?