A few thoughts:
I'm amazed at how far down Trump has brought politics in this country. I was thinking back to the debates 4 years ago and while contentious they were about policy. With Trump its about nonsense.
On what planet did Trump win a debate because he didn't pick up a chair and wing it at somebody? He looked like an unhinged jack ***, which is what he is.

A big part of debates is, can you picture this person as President. Who after 2 debates can truly picture Trump in the WH? His debate performance was about getting adulation from alt-right websites.
For Hillary, I sense a tactical decision not to get into a back and forth with Trump as she did leave some put downs on the table. I'd say this happened for several reason. One is she's playing with a lead here, so do no harm, and the second is I'll bet they have more nasty stories ginned up for him this week.