Yeah, well that's true. Martin can skate though. He can do a number of little things. He's an effective defensive player and penalty killer. He will put up some points. He's a bigger body than Callahan--a little bit stronger IMO and a pretty good fighter. Very good at tracking puck carriers down--that comes with being able to skate. IMO he edges out Prust as a player--bigger, better skater. Prust IMO is a slightly better fighter. If I had to choose I'd take Martin. I think he led the league in hits last year.
If he's willing to drop the gloves, at that point unless it becomes an injury risk, I don't care how good of a fighter they are. Losing a fight can ignite your teammates just as much as winning a fight.
When it comes to hockey, fighting ability (not willingness) is about as important to me as whether or not you tuck your jersey in.
I'd rather have a 5 goal scorer that loses every fight than a 4 goal scorer than wins every fight, all other things being equal.