Dragons are indeed amazing, but like the others, I can't really see them work well in the D:OS system. They were already hamfisted in Dragon Commander, and in such a way it was a chore to use them and you ended up doing TBS without ever turning dragon, such a loss...
I would be all for a Divinity III with Real-time dragon flight though
(and imagine what they could do if they kept the area effects from D:OS in)
