To say they are almost always different is clearly fooling yourself. The jobs are always similar in most ways. The summons have always been similar in most ways and hold their nostalgic value. They make changes the combat system and different ways to customize, but it's still always been the same concept.

If I really cared enough I could go through every single final fantasy and point out that they've always had the same jobs that always had the same similar concepts. Unfortunately, it is pointless if you are seriously kidding yourself, that they aren't. Have you even played any of the earlier final fantasies? Like, before 7?