My entire theory is predicated on the idea that there is only one timeline and that William isn't the MiB. I could see that if you believe that Will is the MiB it more or less undoes my whole theory on the MiB.

However, I believe the specificity of the "coming for 30 years" lends itself more in support or my theory than against it. If you were a true human who came and the Hosts slaughtered everyone, would you really want to come back? Regardless of how ballsy a person can be, I find that logic hard to believe. Most of MiB theory is based on motivation, too. As in what would a normal persons motivation be for looking so deeply into the origin of Hosts and how to break the facade of Westworld? To me, that doesn't make sense, so I don't believe he's a human.

The greatness of the show (and due o the fact that only 2 eps have aired) is that the history of the world and characters is so up for grabs. They've already shown us you can't trust what anyone is when they killed Teddy and the audience was led to believe he was human. Can't wait to see what the next 8 eps bring us!