BastementSparkle

Well, I'd imagine Gen 5 would be what they'd call something set in a new universe, while something else set in the world of FIM would either just keep being Gen 4 or a Gen 4.5.

Perhaps Equestria is just a continent.. and Gen 5 will be set on ANOTHER continent on the MLP:FiM planet..?

It's possible, though they could easily just keep calling it G4/4.5 in that case. Really, there's no way to know how they'll got about future Generations. If they'll want to keep the G4 world as just that, only G4, or make the G4 world the general "MLP" world going into the future. Equestria Girls/Guardians of Harmony are both G4 still, despite not being "FIM".