Spin-offs are ok (Dissidia, Crisis Core, Crystal Chronicles, etc...). But don't mix the renamed games like the SaGa ones (FF Legend for the GB) or the Mana (FF Adventure for the GB) with the reall FF games and spin-offs. Those are only part of FF history in the west. But they have in fact nothing to do with the series.
Just my two cents.
As for what game series you should do next, what about Castlevania, Metroid, Suikoden, Shenmue or Metal Gear when it comes to games, or Square-Enix, Nintendo, Sega (or AM2), Enix, or Konami, when it comes to game companies?







