Everyone has a shot. Doesn't mean they are nearly as good as the Pats. I still think the Ravens are too banged up and the Texans can't compete with the elite teams in the league. That said either of them could score an upset.
You think the pats are not vulnerable ? Did you see the games vs SF and jax ? Sure people will say they were tired and disinterested but pats are by no means perfect and being the best team in AFC is debatable. If the pats had lost that jax game people wouldnt have blamed tiredness or injuries. They are good but anybody except maybe indy can come beat them.