I think the Earl of Oxford was proposed by a few, too. And Bacon. I once read a book called Bacon is Shakespeare. I found that convincing, too.
The best argument against Shakespeare the actor being Shakespeare the author is that actors then were like actors now: low-lifes, ignorant, etc. I like theories like the ones mentioned because they make me more interested in the history of the time.
Actually, I believe that the Bacon theory was proposed by a Ms. Bacon, a descendent of THE Bacon. I think her motives were mixed in proposing her theory.
Whoever wrote Shakespeare's play was a remarkable writer and had a very consistent style. It would be almost impossible that Bacon is Shakespeare, because there is a lot of his writing to compare against. If you compare Shakespeare's writing to Bacons's, it's very clear the same person did not write both.