I just don't see how that works.
6 seasons of clues that suggest Red isn't who he says he is.. This whole season has had Liz convinced that Red isn't really her father. Garvey died thinking Red was an imposter, Jennifer walked off in a huff.. thinking Red was an imposter. We've MET the doctor who gave him surgery to look like Reddington, and we've found the Real Reddington's bones.
Those would have to ALL be "fake clues". Look how angry people got at Lost, over the idea that the whole show was 'fake' and that the ending made it look like they'd been dead the whole time.
This would be the same thing. 6 seasons of a 'gotcha' and the "big mystery" of Red... turns out to be that there is no mystery. Liz was just confused.
You might be right. But that would suck so hard.