Pros: Mark Messier is one of the greatest leaders in the history of professional sports, and his Stanley Cup-winning season will always make him a hero in the eyes of Rangers fans.
Messier is currently the special assistant to Glen Sather, and while he has never been a head coach at the NHL or the American Hockey League, he would command respect merely by walking into the Rangers' locker room.
That's a significant part of the battle. Messier may be a nice guy in the public eye since retiring, but one fierce look at his players and they would know who is in charge.
If he is committed to a coaching career, it would be very reasonable to expect Messier to be successful because of his intelligence and work ethic.
Cons: Messier has to decide whether he really wants to be a head coach and whether he will commit himself to the job. It's one thing to picture yourself as a Stanley Cup-winning head coach, it's quite another to spend hours and hours at practice, scouring tape, dealing with the media and coming up with a game plan.
Since he's never done it before, he won't really know it's for him until he lives through the experience.
Verdict: It would be a gamble to hire Messier as head coach because of his lack of experience. But if he really wants it and understands what it takes to become successful, it seems likely that Messier would be an excellent head coach. It would certainly be a gutsy decision by Sather.