One word: Musketeer
They've already proven with arcanist that they are using to at least some extent what was there in 1.0. Also, limsa is still the only city with only two classes, and of course, the musketeer just fits perfectly in the limsa theme.
What it will be as far as role is concerned...not even going to try and speculate, too many possibilities. Either way, the next time there's a content update or expansion where they try to be elusive and just say "a new job is coming" you can be pretttty sure it's musketeer