Some thoughts:
- Does he main a priest or another healing class? If so, he can also claim clinical experience off of this. Ditto if he uses First Aid.
- Does he give gold to the poor or help report gold sellers? That can help check Community Service/Volunteer - Not Medical/Clinical.
- Bonus points if he plays an under-represented race.
- On the other hand, if all he does is go stabby stabby with his rogue or Fury-spec'd warrior, he might be better served by keeping this to himself.
On a serious note, the application isn't there to account for everything that a person does. Certainly, applicants are encouraged to personalize their application by listing hobbies and the like, but to mark his in-game activities as "Leadership" on AMCAS would be a major stretch (even from the viewpoint of a fellow gamer), and a sign of poor judgment and self-awareness. The most I can see is listing this as a Hobby.
As a fellow gamer and younger adcom member, I personally enjoy it when applicants list games under hobbies (especially if it rose to the competitive scene). However, not all adcom members are as liberal, and I'm certain there are older adcom members who might see the listing of thousands of hours of gaming time as potentially being a waste of time, and/or something that shouldn't have been included. Ultimately, you can't please everyone on the adcom, and applicants should exercise appropriate judgment and apply with the application that best showcases who they are and why they will make an excellent physician and colleague. Of course, anything put on the application is fair game for scrutiny. Just my thoughts.