ROFLMAO. "In Final Fantasy MMO's" what are you talking about? Square-Enix has in fact made THREE classes in a Final Fantasy MMO that have significant access to both White and Black Magic. In Final Fantasy XI the Red Mage, Scholar, and Geomancer all have access to both White and Black Magic to varying degree's. So don't you go telling me that it would never happen in a Final Fantasy MMO. And no, the Scholar of Final Fantasy XI has absolutely nothing in common with the Scholar of Final Fantasy XIV: A Realm Reborn aside from their fashion sense.
As for what the Summoner should or shouldn't be. Historically the Summoners in the Final Fantasy Series were either primarily White Mages (although there was one instance of it being a Black Mage) with the additional ability to summon monsters to aid them in battle, or the summoning ability was an ability that all characters had access to regardless of what their primary occupation is. I mean Cloud Strife and Squall Leonheart both had the ability to summon Bahamut to their aid, but they were both primarily sword-wielding bad asses, not summoners.
Point is, the concept of a "Dedicated Summoner" class is something that is relatively new within the Final Fantasy Franchise. You only really see it's presence in Final Fantasy XI and Final Fantasy XIV: A Realm Reborn, and in the case of the former people generally prefer the Summoner to be a back-up healer instead of being a dedicated Summoner. In fact it is only in the case of Final Fantasy XIV: A Realm Reborn that the role of the Summoner is so well defined that it actually has a specific job to do in the party instead of being relegated to doing something it wasn't intended to do.
