I think that trainers do more than just “train.” I think that most people need somebody to help them schedule out their workouts. The trainer makes sure that when the fighter comes to camp, he doesn’t have to worry about what is going on. If trainers weren’t important then no higher skilled professional would ever switch trainers.

I do think that there are exceptional fighters who are good regardless of their trainers which gives their trainers more credit than deserved (Roach for example), but there are some trainers who I think get maximum potential out of good fighters (Garcia for example).