What changed for you? I despised not having full control of my party. Personally I prefer depth of the system and the storyline WAY over ease/difficulty.
Honestly Square just needs to transition the FF franchise into pure cinema at this point...
Yeah, I had my gripes with the system, like not being able to have full control over your party. What I did like though was the fact that you were healed every battle, even though some hated that.
For me, this got rid of the tedious of unimportant battles in the other FFs that just slowly drained on your health/mana, making you use potions or trek back to a heal spot. It also let them to ramp up the difficulty on each encounter, so that you can have many involved battles instead of countless uninvolved fodder with only the bosses being difficult/engaging.
My favorite battle system is still X though. Something about the way it is turned based, yet still quick if you want, and also shows the order of the turns. I also thought the sphere-grid system from X was fine. I disliked the characters and story, though...
FFXIII had mediocre characters and story, but that can be said for most final fantasy games. This isn't Shin Megami Tensei/Chrono Trigger/Mother here.