Don't get me wrong; it's terrific acting all around, and a fairly good couple of stories (clashed together ... sort of 'I wonder what happens if ... oh ...")
If it had come out before the WEDDING CRASHERS-gang had written The Comebacks, The Game Plan is one of the movies that would've had its three-minute spoof there.
If it hadn't been out by then, I guess I'll have to get my mind started on another 'idea ahead of its time'-script for the Farrellys to reject!
As I can see from the Community rating, the 'experts' (who all have faith in Hollywood enough to see each "project" through) know that--while it is a worthy brick in the wall--it's still just 'another brick in the wall.'
Non-experts (or "most people") don't want 'another brick in the wall.' They each have at least a wall-full of those at home (a.k.a. 'books').
Yes; with this movie, I would also much rather close my eyes and remember how the book went!