The one big difference in this year's debates was the crowd control. On each night, the moderator gave stern pre-debate warnings to the crowd (as seen on C-Span) that noise of any type would not be tolerated. And it worked well!
That alone made it rather difficult for either of the candidates to have a "There ya go again" or "You're no President Kennedy" moment that pandered to their supporters in the house.
Debates, after all, shouldn't be a game of trash talk and "gotcha" one-liners, but rather a discussion of the issues at stake. With the pre-debate audience admonishments to shut the hell up, the focus has instead been on the candidates and their positions as opposed to the cleverness of their joke writers. A victory for substance over sillyness.
I'd say this series of debates, therefore, has been quite an upgrade over our previous outtings because of it. Kudos to both the debate planners and all four moderators for job's well done! It was a small victory for both America and Democracy at a time that we could well use one!