I think this would make leveling in the Cata zones more exciting, especially for those of us who actually enjoy playing through the zones storylines.
After leveling several alts 80-85, I have realised there’s pretty much only one way to approach leveling if you don’t want to get to max level without unlocking all the reputation tabards. Getting friendly with each faction and finishing every dungeon atleast once through RDF is pretty much enough for finishing 80-85 completely.
If the tabards were instead BoA, you could approach leveling differently and mix it up a bit more, instead of being forced into one single route only. That way I could finish Vashj’ir on alt one and Mount Hyjal on alt two, without missing out on too much along the way.
To me this seems like a very simple change that’d improve the game.