FF12 could have had the exact same multiplayer system that games like Tlaes of Symphonia (or Abyss) had, and been the exact same game but more fun. Those basically did what Xav wants, and that is 1st player controls EVERYTHING outside of battle pretty much, but other people can join in during the fights as whichever character they want. They totally could have done that for 12...but I don't really mind one way or the other.
And Elcura, FF9 is my most favorite game in the entire universe, and I love how you keep pointing out how good it is/how they did things right.
Also, I was thinking about this. In FF10 if you want all your characters to have the same sphere grid you need to work for it. Since you NEED locks to get to certain parts, and like a LEVEL 3 SPHERE GRID MARKER thingy to unlock certain things, that meant you had to go to places and farm for them for sometimes hours just to get 1 little thing. It took work. Unlike in FF12 where all you have to do is buy 6 TPx2 trinkets or whatever and just go to an easy zone and put your lazymode gambits on for 20 minutes in order to get like 400 TP. To use in the exact same spots on all your characters.
Yeah you don't HAVE to put the shit in the same spot, but why wouldn't you get +HP for each character, and more STR for each character etc.?