"I think that even though there is a "bias" against Senators, the fact that he was a Governor first, should help him."
It's more than that. The bias against Senators is that they don't have major administrative experience (ie, they were not governers). He was, so that is no problem at all. Senate experience is, in fact a big plus, since knowing how the Senate works (like Bush doesn't) is important.
Plus, he won't have been in the Senate so long that he will have a long history of votes that could be used against him..