If I was a member of the Hall of Fame selection committee I would hold off on voting for any candidate who played a role that has unfolded over time and doesn't have a long list of players that serve as good points of comparison. You're seeing this now with the designated hitter, and you'll see it even more with pitchers as relievers who are NOT closers become more and more important in the game.
The NFL went through a period like this with tight ends. It was a long time before the first one was inducted, and there are only eight of them in the Pro Football Hall of Fame today.
I say Sutter belongs because he changed the game. He introduced, or at least was the first master. of the split fingered fastball. His first few years he was unhittable.