How come patrick stewart is not billed better?

Order of appearance, likely.

He got the last position, which is just as sought-after as the first. So many films have that, "and featuring X as Y" credit come up right at the end (I'm pretty sure Sean Connery got it in The Untouchables). It seems to be used for situations exactly like this one where the biggest name they get (Patrick Stewart) is playing a smaller character (the villain, here, or a mentor with Connery). The lead character still gets the top billing, but they save a sweet spot right at the end for the big-name guy to get his due.

Lol. I didn't even know it was him, till the credits. Well done, Pat!