Well, they changed the battle system to add some more reality to the games (at least that's what I'd guess). I personally found the battle system in XII enjoyable. I have yet to play XI so I cannot talk from personal experience, but I have seen the battle system and it would appear to me that it would be impossible to incorporate the old turn-based system in an online game in which you interact with other people. So, there isn't really a problem with either battle system that I can see.