I think that adding the ability to change your rep with different factions should be added to the server in an upcoming patch, this goes for cross faction too... yes i mean Humans being able to chill with Thrall.
This might seem dumb, but i think that it would be a great way to make your character even more unique. For example: I play a Dwarf, but mabey sometime in his journey throughout Azeroth he gained the respect of the Tauren by trading rare artifacts from Ironforge with them. Or mabey he was traveling through Mulgore one day and rescued a Tauren that was being attacked by Centaurs or something and that tauren introduced him to Cairne and he was from then on welcome in Thunderbluff.
One last thing: I think that characters will have to choose their rep upon creating their character or when they first enter the game, after this they will no longer be able to change it to whatever they want and they will have to quest if they want to gain any more rep. This would be to prevent... for example: a bunch of allys running all of the way through org... gaurds waving at them with smiling faces, and then once they get to thrall, switch their rep and now Thrall is dead (of course Thrall would just own them all because he has magical 1337 powers and would blow their heads up with his lazerbeam) but still, hopefully you get the point.
Just a suggestion, BTW my characters name is Gruslin, and i would actually like to RP a dwarf that is friendly with TB