IMO this might be the most boring debate in decades. Hillary needs to be able to stand up for 90 minutes. Trump needs to look Presidential for 90 minutes. Makes no difference what come out of their mouths. If both happen it is a tie.
HOWEVER! WHAT YOU FAIL TO CONSIDER -- IS THAT HER TONE -- HER HECTORING, ANGRY, STRIDENT, BITCHY TONE -- YOU KNOW WHAT I'M TALKING ABOUT! DON'T DENY IT! THAT TONE JUST MIGHT UPSET SOME PEOPLE!
Much of her campaign is based on Trump's lack of emotional control. If he is presidential (and he will be) and she is bitchy, it will look bad. As you say, the words they use won't matter all that much. But she could sink herself. She has a tin ear.