Given the end of Divinity 2, A theoretical Dragon Commander 2 seems like it could be set right after that game.
A playable Dragon in a turn-based game, or one with such a small map size as D:OS would be an underwhelming and less interesting use of a playable dragon.
Speaking of engine changes, Dragon Commander 2 would probably also be best served by further modifying the engine to allow for bridges to allow for movement of land vehicles across and ships below. The lack of bridges in DC limited the value of ships quite a bit.
But really, it's highly unlikely we'll see a Dragon Commander 2.
