I also agree Zoro vs mihawk won't happen. Zoro is too emotional guy like Luffy, no way he is going to cut the guy who helped him. I think Mihawk know Zoro’s heart, so this is a good way to avoid fighting Zoro, since Zoro will be emotional.
Look at Luffy vs Fujitora, Luffy couldn't even fight at full power because he likes Fujitora. How can he even fight Shanks, if he can't even fight Fujitora and how Zoro can fight Mihawk, who trained him for 2 years? This is the guy who doesn’t want to cut naked men and doesn't want to cut women. Zoro vs. Mihawk won't happen for Zoro being too emotional.