Spitzer has been overplaying his hand, appearing like a bully against the Senate Republicans and allowing those Republicans to form an alliance with Bloomberg. I expect certain others to chime in differently, but at present he is losing that battle politically.
I can't really understand why he's giving a demoralized NY GOP anything to actually fight for at this point. Being a little more concillatory would probably have strengthened his hand (and he would have gotten more passed).
In short, the honeymoon is over. These numbers are not surprising.
Blunt's numbers may be an outlier, maybe not. People have been writing him off too quickly, like Daniels, even though I find amusing writing the conclusion for the IN race on polls that are at least 9 months old.
I wouldn't say Spitzer has overplayed his hand, he is fighting to do what he campaigned to do. try to bring change to the way the State Assembly and Senate worked. His tactics may have turned off some people, but when it comes down to it I think it will pass, especially as the guy he has clashed the most with could very well be in legal hot water (the State Senate Majority leader Joseph Bruno)