No, He could still work, but the problem for months now is we know he signed the FISA Warrant to start this crap. You can't hire Muller and be part of the conspiracy. This is why they won't declassify the documents.
As "Bones" would say,....He's dead Jim. I think the Sheite storm is coming to the Dems. Hillary could get re investigated with the new guy in charge. The whole upper FBI, CIA, NSA, could be involved. Brennan is already crying Constitutional Crisis just over Sessions firing.
You aren't supposed to use the law as a political weapon, but I think there are many that have been waiting for just plain everyday Justice for some of the swamp rats. I don't think Trump can demand the AG prosecute certain people, but there are about 20 easy wins if you go back to Benghazi and Fast and Furious on up. This new guy probably already knows where the bones are buried but had no power.
I think most of the upper echelon know where most of the bodies are buried.
That is why I consider most of what happens to be merely Kabuki Theater for the uninitiated.