I think flixerflax has a point - the monsters called as wyvern in this game do look like my avatar here. Besides, it's a good choice, since medieval wyverns often looked like that, and the wyvern as a sort of dragon is a more modern depiction.
This of course causes the problem of how to define a dragon with two limbs and two wings as opposed to a dragon with four limbs and two wings. I propose to call them "drakes", in this forum, to avoid confusion. So we will have: wyvern -> birdlizard monsters of the game; dragons -> four limbs and two wings, the main creature of the game; drake -> two limbs and two wings, it's a dragon knight turned into a dragon.
About the game controls. I would really like to know if the pc version will indeed feature a good joypad support? Maybe it's just my impression, but I think that flying around with keyboard controls may be a bit unpractical, at last for me. Besides: if there will be joypad support for the pc version, will it also be possible to change the pc interface to the same interface of the xbox360 version?
...Oh, and are we sure that the dragon knights are humans who work for the dragons?