Shakespeare was the real Shakespeare. As far as I know it was reasonably common in those times to change your signature about alot and it is a fact that he (very occasionally) collaborated with other play wrights to write some things. I don't think any of the conspiracies really stand up to be honest.
I don't think we need to, nor should we ever, really need to debate that.
Even if it's determined that a bunch of other writers contributed to Shakespeare's writing (which I believe is part true), Shakespeare will still be remembered as a huge force of literature.
He/he+his compadres will still be remembered for the thousands of new words he/they brought the world.
It's an interesting question but one I doubt we'll find the answer to. I've never really heard of this debate before but some of its points (uneducated commoner becoming such a brilliant writer) do make sense, but it could also explain why he was such a good writer if he learned (the words he introduced could of been words he heard, "common" slang or something like that). But, in the end, does it really matter, he was a good writer and wrote some brilliant works, some better than others in some peoples opinions, and no matter who he really was his works will live on for hundreds if not thousands of years. Isn't there also a debate that he wrote more interesting female characters as he enjoyed playing them?