I think it is a bad idea to kick Burris out, or force him to resign for a couple of reasons.
First, it is inevitable that a liberal will be appointed. If you get rid of Burris, someone at least as liberal, and probably worse, will be appointed to take his place.
Second, he will be a weak Senator because of this scandal. He is already damaged goods. If he has an agenda, he will not be able to advance it. He has a poor reputation even among liberal democrats, and no one will want to have anything to do with him,
Third, he will be easy to defeat in the next election cycle. Because of this scandal, he will be easier to defeat than most any other Democrat. Why replace a weakened, scandal ridden liberal who is going to have difficulty in the election with someone better?
I think the Republicans should just shut up and stay out of it. Burris is a no win situation for the Democrats.