As an ex-wrestler--
I think you can't really put them against each other. I mean, it's like asking who would win, Michael Jordan VS OJ Simpson.
Wrestlers spend their entire time trying to be quick, agile, light, strong-- using their entire body.
Boxers try to be quick, agile, light, strong-- but they're best at pounding up meat with their arms.
Although-- if I had to make a stance-- I'll say Wrestler cause they move like lightening and take control of the boxer's head. Boxers would be like, "I'm gonna pound you--uuughhh... let go o' mi head! I can't breathe!"