One thing I think would be interesting is to grade the skillset of each street-level hero's principal martial arts from 1-5, with 1 being rudimentary understanding and 5 being elite-level mastery.
For example, Wildcat, a world champion boxer with a probable focus on Western combat systems, might be:
Boxing: 5
Kickboxing: 4
Wrestling: 3
Judo: 3
Jiu-Jitsu: 2
Batman, well-rounded in nearly all Martial Arts, would be:
Boxing: 4
Kung-Fu: 4
Karate: 4
Muay Thai: 4
Judo: 4
Jiu-Jitsu: 4
Black Canary, who is a little more petite and kicks more, might go:
Boxing: 3
Tae Kwon Do: 5
Kung fu: 4
Judo: 4
Jiu-Jitsu: 5
Something like that.
It gets harder with the super-powered characters, as they'd be adapting the art, rather than mastering it as it exists.