Jack Nicklaus has had the best answer -- for years now -- and it's regulating the ball they use. Certainly, the ball manufacturers have the technology to tweak the flight distance, and each pro could still use his preferred brand. That way, a number of classic old courses could be returned to competition -- simply adjust the ball to the course. Everybody's distance control numbers would be affected -- but, they are pros and all are affected, so let them adjust. It wouldn't be too hard to make balls for tour pros that work at, say, 6400-6600 yards, 6600-6800 yards, 6800-7000 yards, and so on.
I have always felt that the pros should use a hole that is smaller than what typical amateurs use, or amateurs get a bigger hole.