It's been pointed out that the ABC moderators of the debate asked a bunch of questions that were trivial, like Obama's connection to William Ayres. There were many like that, which were seen as validating right-wing concerns (capital gains tax) or right-wing character charges (patriotism). But here's the interesting point:
The debate was primarily to help Democrats in Pennsylvania choose a candidate.
And having Clinton and Obama discuss right-wing talking points does nothing for the Pennsylvania primary voter.