That makes sense, I agree with the thought process about including the whole playoffs. But let's take just the regular season... there were 3 other QB's with better stats than Manning (Brees, Rivers, Warner), and the case can be made that Rivers and Warner were just as important to their team's success as Manning's to the Colts.
Philip Rivers had a statistically better season than Manning in pretty much every single category. Like Manning, he became the centerpiece of his team and a huge reason they were able to pull themselves out of a hole. Manning won MVP. Philip Rivers beat Manning head-to-head.
The only thing Manning had over Rivers this season was more wins and a bigger winning streak. But Rivers stats plus beating Manning head-to-head kinda made me think twice about the timing. I think if Brees' team made the playoffs, Brees might've won it. Honestly, I think it if were any other QB in that spot instead of Manning, that guy wouldn't have won it. Manning's name just carries a lot of weight, and rightfully so, he is a great QB.