The key thing to understand is that Marvel is CHEAP thrifty and they would rather give opportunities to obviously talented but underused directors and actors than spend a fortune on someone that everyone knows is good.
Plus they have a pre-existing relationship with Joss on Runaways and Astonishing X-Men.
A lot of what Marvel is doing is convincing people to do their films for less (and signing them to multiple film deals) because being in a "cool" comic-book movie that makes a ton of dough will help their careers.
The Parkman-Mohinder idiot shouting matches were hilarious and a little bit gay, what with Mohinder mounting Parkman after their slappyfest bitch fight. I cracked up at the stupid round-and-round. Mohinder: