If Dragons are really big versions of ordinary enemies with ordinary enemy AI, and the craptastic ordinary enemy "flying" (hovering), then I'd rather see none. On the other hand, if fighting dragons was really well done, sort of like Shadow of the Colossi or something, that would be cool.
Indeed. A more interactive fight with the dragon itself actually being a platform like Avion in Shadow of the Colossus http://www.youtube.com/watch?v=1o56kQtAbBo would do justice to the dragons.