Not necessarily, ideally it should be a mix of all 3.
Also raid fights could unlock a special spirit bind in certain items, or drop certain items which could then be used in the creation of a special materia. Honestly... That would be more than enough to ensure that raid content is properly rewarding for the effort. It could even be tradeable so the casual raid haters don't have to complain about it!!
I would like thatevenmuch better than making the crappy Darkhold gear better.