Maybe Scott Brown is pushing this issue, and he is, to play on class resentments. Now that's an issue with some meat on it. Elizabeth Warren represents a liberal/academic elite that supports higher taxes to fund ever more government programs. Personally, I'm not sure whether Warren in fact supports higher taxes, but I've met enough academics who do, so why should I check out her actual positions? That may not be my attitude, but I bet it's a common one.
The Real MassachusettsI realize the Massachusetts is supposed to be a true-blue state where these liberal views should win hands-down. However, Massachusetts actually has a lot of blue-collar workers. (All states do--they perform those important service jobs.) We often elect Republican governors, including from 1990 to 2006. We have a flat state income tax, not a progressive one.
The election of Scott Brown in the special election in 2010 showed that our habit of electing Democrats to the Senate wasn't unbreakable. Brown won a clear victory over Martha Coakley, a decent Attorney General (in that she hasn't had a major embarrassing scandal), but a cold-fish as a campaigner and a typical, uninspiring liberal.
Pluses and MinusesElizabeth Warren has a better resume than Coakley as someone who understands financial issues and headed up the reform for consumer credit. However, her academic career and her talking points make her sound like another hack liberal. Nonetheless, I don't think she is. With her solid understanding of financial issues, she could be quite an asset in the Senate.
This isn't to say that Scott Brown doesn't have strong points too. He has been a swing vote on some issues, like the repeal of DADT. However, on other core issues like budget discipline (the sequester) and repealing Obamacare, Brown talks just like any other Republican. He's not a bridge to compromise on those weighty issues, so he's better than a typical GOP senator, but not by much.
So who has more appeal in Massachusetts? If it was a race of a garden-variety liberal against a truly independent moderate, I think the moderate would win. We don't have a majority of true liberals here--just 30.3% according to Gallup. However, Brown isn't as moderate in his votes as he pretends, and that may be his undoing.
The race may hinge on personality, not issues. If that's the case, Brown will win if Warren continues to sound like a hectoring liberal academic. But Brown's supporters better stop acting like spoiled frat boys with their mocking war whoops. I doubt that's the way to convince independents.