Since the question was "What makes a great bowhunter" and not "what makes a bowhunter successful" I would say that the taking of animals has to be in the equation somewhere. I think a bowhunter can be successful without being great.

To be great, one would have to have intimate knowledge of the prey, and be able to apply that knowledge to overcome the games superior senses with the end result being the taking of the animal. One can be a great hunter without a record book animal, but I think they have to routinely take animals where others fail. The kind of hunter that makes others think they must be cheating to get the results they do... those are great bowhunters.

To be a successful bowhunter...well, those are the intangibles.