I've got enough characters leveled up that if I really need to, I can cheese whatever encounter with a Ret group (or not even Ret, just brute force). I don't synergize because I need to, I do because I want to. Half the fun for me is making optimized teams for each. It's not exciting to do the same thing on every fight. I do miss Vit0 though. And occasionally I'll do Ret, but generally because the fight strategy calls for it specifically. I could go mage group, too, Vivi, Lulu, and Golbez are all 65 and they have unique weapons. Rydia, Hope, Terra, Ashe, Rinoa, Fusoya, Tellah, Strago, Reno, all 50+.