Al Ewing would be my first choice, especially as a fresh new voice. That said, I'd be perectly happy with either Mark Waid, Peter David or James Robinson taking over (surprisingly enough, they are one right after the other in the poll).
Peace
Jason Aaron
Rick Remender
Charles Soule
Kelly Sue DeConnick
Al Ewing
Nick Spencer
Brian Wood
G. Willow Wilson
Mark Waid
James Robinson
Peter David
Dennis Hopeless
Kieron Gillen
Simon Spurrier
Other
Al Ewing would be my first choice, especially as a fresh new voice. That said, I'd be perectly happy with either Mark Waid, Peter David or James Robinson taking over (surprisingly enough, they are one right after the other in the poll).
Peace
There's a few reasons. First, she hasn't been at Marvel for very long, and she only had a couple books under her belt before going to Marvel. She doesn't have that much experience yet, so the question is whether she's ready for the main Avengers title. There's also the matter that she hasn't had a team book at all yet, only a solo title.
And if I'm honest, I kinda think institutional sexism is a bit of a factor, though less than usual for these sorts of "Who should write it?" threads. Any time someone makes a thread asking who should be the next writer on any given book, unless it's a female-led title, 90% of people are going to go with a male writer. If the thread is asking who should write, say, a Wasp series, then KSD, G. Willow Wilson and Kathryn Immonen will all get plenty of votes. Ask who should write Iron Man, and the overwhelming majority of the votes will go to male writers. Very, very few people would name a female writer as their first choice on any title that's not female-led.
Personally, I'd like to see Roger Stern or Kurt Busiek come back and write some truly monumental Avengers epics!! Although, for my money, Roy Thomas was and is the best simply due to the strength of his run from volume 1 issue 71 through the Kree-Skrull War (issues 88-97). Now THAT was THE AVENGERS!!