That is a really, really interesting idea. Of course, my first thought is that erasing River means the Tenth Doctor dies back in The Library, but maybe time heals around that somehow. (Most likely that potential paradox wouldn't even be mentioned, though.)

I'd be sad to see River erased, but happy that Amy and Rory get baby Melody back . . . and it would let Moffat get the final word on the fate of River . . . and it would also be pretty epic.