Cuomo isn't on the record for advocating anything that would be contentious in a Democratic primary like Schweitzer and gun control. He's continuously toed the line in his governance as a Clinton-esque centrist, but he wouldn't campaign on anything fiscally conservative. The left would be right to point to his record, but that's nowhere near the same problem as running for the nomination as, say, Huntman's views on climate change or Brian Sandoval and abortion.
Cuomo is just going to try and paint himself as Slick Willy's protege.
Why should Democrats support that approach when Slick Willy's wife, a true blue liberal, is available and by far more electable?