There's wanting more options, like more hair styles or fashions, but this is more akin to adjusting game play. Adjusting game play requires more effort than flicking a switch on the server to change something's accessibility. There's the matter of game balance. And I hope to the Twelve you mean only class abilities (though I already mentioned how that'd be questionable), Job abilities would break the game entirely (as well as not work at all given all Job abilities are quest rewards. Extra Jobs are special). Hallowed Ground seems the popular example but there's others that are just as game breaking, like Benediction or Spineshatter Dive.