Kakashi is definitely the better choice for Hokage.
As for a fight, I know people are automatically gonna say Naruto but think about it for a second. We're talking about Kakashi who has been watching Naruto fight this entire time and knows his student pretty damn well, he's seen him pull out a lot of tricks. We also know that Kakashi isn't just PS and Double Kamui, he's damn clever and has an arsenal that can easily catch Naruto off guard at times. With Kamui snipes (one that works faster thanks to having both eyes) and being able to go intangible, plus a Susano'o to stave Naruto off at times, defense is covered. Speed isn't a factor here since Kakashi has been able to stop multiple attacks from Kaguya and react well, he even managed a good hit on her. Naruto has better striking speed than Kaguya but with Susano'o, intangibility, and Kakashi's reflexes lately, that's a small factor. And at any opening, Kamui snipe is GG. Current Kakashi is essentially him, Obito and Sasuke all in one.
So in a fight, I say Kakashi beats Naruto high-extreme high diff. I see Kakashi winning more than I see Naruto winning.