I've read a bit on the various claimants and the arguments put forth and think that there's this thing called "genius" that is often claimed and rarely achieved, that is in play (pun intended) here. I'm open to the possibility that Shakespeare collaborated with Christopher Marlowe in the Henry VI plays.
Marlowe had popularized the use of blank verse around the time that Shakespeare began his career, so Marlowe's influence was there, even if there was no direct collaboration.
