I assume that's the reason why it is not ingame yet. Although reputation had a greater influence in vanilla/bc/wotlk (remember Gelkis/Magram), much of this has been removed from the game. Yet there are enough reputations ingame that have influence on how NPCs react - partially mutually exclusive - (for example Steamwheedle, Scryer/aldor, Oracle/wolvar), so making them account-wide is not as easy as it seems.