Maybe I'm delusional but I clearly remember filling out a survey from SE with one of the questions asking about this very thing. Or something along the lines like "would you play it" and if we're going based off of the pattern. XVI would be a Single Player RPG and XVII would be the MMO since XI was the MMO, XII & XIII were RPGS. I personally don't think Hack n' Slash type playstyle similar to BDO, BnS, and what not would work very well for a Final Fantasy MMO. Then again FFXV is pretty fun but the combat after a while seems very dry and repetitive. Maybe who knows.