I guess it depends on what you consider MVP really. To me, it's the person who is most valuable. That is, who brings the most value to their team. AP brings lots of value to their teams offense. Peyton Manning brings value to the offense just as much so or more so than AP, but also to special teams AND defense. So he is more valuable imo. So.. MVP.
I think he should get comeback player as well. Knee surgery? Happens all the time. Yes, AP did great after a knee surgery, but Peyton had NECK surgery. How many players have you heard about receiving multiple neck surgeries and then playing in the NFL again? When I first heard the news when he was still in Indy, I felt bad for him - I figured his career was completely over. I knew AP would be back at some point. I didn't think Manning would ever be back.