In debates Trump does not insult people as much as is claimed. He does negative marketing. Specifically he figures out one thing about his opponent that give people an emotional reason to not support them. He then packages it as a catch-phrase label that sticks in the mind, with Jeb! it was "low energy Jeb". This kind of targeted labeling is effective for turning people off to a product.
Now on twitter, Trump will get childish sometimes when something upsets him and get in the gutter with insults...similar to the flame wars all to common on FR now-a-days. But that is not what he will do in the debate.
Now the problem with debating Hilary is to limit oneself to one negative marketing catch-phrase among so many possibilities.
I admit to being a newbie here, But I can't recall when there were not "flame wars" on FR.