You'd hope. The concern is though that this election and US politics in general have been dominated by personalities instead of politics. That mainly applies to Trump but it can arguably go for Clinton too in that she's been painted as this reliable establishment figure of sorts. I don't think she's a particularly impressive public speaker and if Trump plays the debates well, not being too outrageous but still making it about personality, he may benefit.
She's a very good debater and one can only think her citing specific policy prescriptions will put her in good stead with the demographics she needs to reach most - White suburban women, Hispanics, Blacks, and moderate Trump-skeptic Republicans. There comes a point in a one on one debate where not being able to offer specifics is problematic, whereas its easily forgotten when there are a dozen people on stage.