Meh, as long as they keep their own twist on the fanservice content I don't really care about seeing FF references everywhere I look.

It's really been a mainstay of the series to have tons of references to older games in the series, usually just in names and certain areas but in a MMO you get alot more play with how you introduce older game references.

Make the gambling arena the Golden Saucer? Sounds good to me.
Adding a Red XIII mount? Not so good to me...

It will all fall down to how it's implemented, and if it's in good taste or not.