I actually hope they don't implement something like this to the game (at least not any time soon) because if they do, it'll probably do one of three things:

1) Be so weak that it's useless
2) Be strong enough that they feel the need to balance certain endgame encounters around it (aka; have the proper setup or have one hell of a time winning... some won't have a problem with this, but I always think there should be more than one way to skin a rabbit)
3) Bring back loljob and leave certain classes left out again, Abyssea's sort of eased that since nearly everyone is god-like but once we're out of Abyssea, we're going to have all new balance issues.