Bettman rescued a league that was way overvalued when he came in and kept it from the total destruction it was heading towards. He's cowed a militant, out of touch players association and ensured the health of every team for the forseeable future - from the sounds of it, if a team can't survive in the upcoming CBA they simply don't deserve to have a team.
Complaints about "marketing" and other such are from people who simply don't understand the NHL thought far more of itself than it deserved to years ago when Bettman came in, ie the Sports Illustrated article. Anyways, Bettman rasied revenues several times over. It is not his fault player salaries couldn't stay sane - the entire pay structure was being forged by teams throwing 60 million on player salaries regardless of team revenue and you can't tell the owner not to do that, not if you want to keep from being sued.
Bettman has saved the NHL. He has been the single thing in its favor since he came in. It's a bit sad that there's still a few out there who hold the delusion that the NHL was on the verge of being the next NFL or something years ago; hindsight shows it was nothing more than a pipedream. Bettman took a regional sport and did everything humanly possible to try to make people care about it nationally. It didn't really happen, but, again, with hindsight, it appears it simply wasn't possible to do, ever, period, and may never be - hockey just isn't big enough in the US to get to that point and doesn't have the grassroots support - minor hockey etc - to grow beyond that.
He may quit, on his high note. But he darn well deserves accolades. Some fans simply don't know enough to understand how much he's done, but that's okay. He'll get by.
