For Hillary? She has to show up with maximum energy, no health issues, no coughing, brilliantly devised answers and not do any bug-eye situations.
For Trump? He just needs to show up.
It's that kind of debate.
There's virtually zero chance that Hillary can out-debate Trump. In fact, Trump's biggest issue is some moderator who asks a trick-question with forty different ways of interpreting the question.
For the moderators? They have to seem like they are neutral while helping Hillary as much as possible and asking 3rd-grade level questions. On the idea of taking on Trump? If the public thinks for one moment that the moderator is the the debator of Trump, this debate is finished and Trump can just grin as he slaps the moderator left and right.
A cough or two from Hillary? Trump can come and say something that would immediately halt the debate and settle the health question once and for all.
A bug-eye moment? Don't even bring it up.
And here's the really sad thing for Hillary.....she has to show up to two additional debates, and repeate a perfect health and stately mind situation. Any stumbles at any of these, and she can carve off hope of winning.