Last night's debate was terrible. It's a bad format to begin with. Most issues can't be fully or very intelligently debated in 2 minute spans. So if your goal is to flesh out people's position on issues, this just isn't the format. No one will watch for as long as it would take.
Even if you don't want to assume that the premise is flawed, last night was handled poorly. Jim Leher asked the most vague questions possible. Unless you are going to tell the candidates the questions before the debate, they need more than 2 minutes to explain their differences on "entitlements". Maybe then they can sum up their positions quickly. But even then I'm sure important things would be overlooked.
The other problem I had with Leher is one that I have with every moderator, which is that they can't challenge the candidates and truly moderate the debate properly. The moderator needs to be able to call out bullshit and push the candidates to explain themselves without bullshitting. Doing this would allow the audience to see how the candidate thinks and how they react to stressful situations. Those are qualities you probably need to have in order to be president.
Until these issues are resolved I don't see much value in watching the debates. Plus the reactions to them are pretty firmly based in confirmation bias. The few people who haven't made up their mind might be influenced. But they don't really matter that much.