It's social issues. Subrbanites are becoming more Dem over social issues.
Suburbanites only vote over social issues when one party is proposing a radical social agenda and actually puts that out there. I think the GOP could actually keep most of their social positions, but they have to just STFU about it. The thing about statements like those made by Murdoch and Akin is not that it hits people on a position that they are obsessing about... it's just that they sound absolutely insane when they are making them.
I think THIS is the problem with the GOP anymore. They make these radical statements about rape, evolution, global warming, etc. and they wind up changing an issue that people weren't really thinking about this election and turning it into a negative. By taking positions that are so ignorant and so stupid and so backward, people tend to start wondering about their judgment when it comes to everything else.