People are going to want to watch the debates live for the same reason people want to watch sports live. You can argue all you want for why a post-processed sports game is going to be so much better, but the truth is that's not what people want.

And the sort of people who are going to want to read a fact-checked version of the debate are in the tiny minority and likely well-informed enough that they have completely made up their minds well and truly before the debate.

I do however think that fact checking is an absolutely great idea, it just needs to be done live. There could be a fact checking team which can interrupt candidates with objections, or ring a "pants on fire" bell, or something entertaining.