I'm so going to laugh if SE announces that Versus XIII is being renamed Final Fantasy XV at the event.

The crystal theme is sorta overused cause technically its usually a major factor in every FF title, so nothing new there, but each of the games has been confirmed to use similar terminology. Agito has l'Cie for instance but whether they are anything like the ones from XIII is up in the air. Versus XIII mentions the goddess from XIII as well though she appears to be playing a much larger part of the story for this title. Basically similar terminology is shared but its being strongly hinted that they are very different from each other in each title.

As an example, say their was a VII Mugglefluff title and it had a group called SOLDIER but in this game SOLDIER are a race of Dragon Knights that protected an ancient kingdom instead of being Mako/Jenova infused super soldiers. That's what's kinda going on here.

Basically SE is trying to reinvent the FF franchise in a way.