My all time favorite battle system is Jobs, and this is basically an addition to that so thats why I enjoy it. I hate being restricted on who can do what in my party.
I like job changing, but not necessarily the outfit aspect. My problem with the costume changing is really that it looks so stupid, and the costumes are awful. In Lightning Returns I was happy moving between her XIII and XIII-2 outfits (also Cloud's to an extent). But every other outfit looked stupid and I hated that part. If anything, the costumes in FFX-2 were worse, never mind the animations. Yes the animations could be cut, but only after watching that transition once. Going from Gunner to Berserker would have an animation once, that wouldn't repeat. But if I went from Lady Luck to Berserker, or Dark Knight to Gunner, I'd see it again.