Watching the debates, voters will be looking to make judgments about both candidates
Romney will certainly be of interest to voters watching, because he's relatively unknown right now (yes, even despite the exposure he's had over two election cycles and everything in-between).
However, President Obama will also get a close level of scrutiny, because of the cottage industry of misinformation and distortions about his person and policies.
Here's how the dynamic should work;
Romney will confirm the worst voters have heard or read about him. He's wrapped his policy around the worst of his personal privilege and greed. The rest is a demagogic and prevaricating attack on Barack Obama's character and record.
President Obama will easily render all of that nonsense, that republicans have convinced themselves he represents, moot and ridiculous. Barack Obama will resemble none of that; instead, the debate will be a welcome platform for his very inclusive, and substantive appeal.
Romney can't sell his economic plan because it doesn't add up. He can't sell his foreign policy criticisms because he's functionally clueless, even with cues from the Bushites advising him. He can't even sell himself. With or without zingers, Romney will be left looking like a spoiled brat who's too privileged and elitist to actually care a wit about the voters watching.