In my opinion, he is a major part of the profitability problems the league has been facing for a while. When he was brought in to the league back in '93, he treated it just like the NBA. He got rid of the traditional divisions (egregious insult to hockey fans), and encouraged expansion to the point that the league still is over expanded, and the quality of play top-to-bottom is worse than what it used to be. The over-expansion of the league diluted the talent pool too much and we witness a lower overall level of play. He encouraged teams to move to bigger media markets, which did not have the fan base to support a team. The NBA mentality that he brought to the league led to a drastic rise in players salaries (blame goes to the owners, agents and players as well), which is one the main reasons for the financial problems they suffer through now.
I'm not even going to mention the rules changes to "make the game more exciting". He wasn't a hockey guy - he doesn't get the sport.
His job is not to work only for the owners, it's to work for the good of the league. 5 years ago, we lost hockey for a full season. We are facing the same situation again. His job is get the players and owners to work together to come to an agreement that is best for the league, and in my eyes, he has failed in the past, and continues to fail today.
All things that needed approval from the owners. The owners approved the division name changes to align better with ALL the other major sports which had geographical divisions.
Expansion was approved, ironically, to save the Kings. McNall wasn't making enough money with the Gretzky era Kings, but was spending drastically on a loaded roster. With a need for money he sold part of his market to Disney, and the demon spawn were born.
Over expansion happened because the owners became seriously obsessed with the expansion fees being paid by the new franchises.
I disagree with the dilution of the talent pool. Sure, every team could be overloaded with stars with less teams, but the fact is that expansion coincided with the rise of the European nations in hockey, in fact, I would say that expansion led to the need for more players, and for the league to look in unconventional places. I would even venture to say that without expansion we may never have seen Anze Kopitar.
The rule changes have to be approved by not only the owners, but also the players association. As an example, the new 4 conference alignment the league was looking at was blocked by the NHLPA.
As for what his job is... he's not an arbitrator. He was hired by the owners, and can be fired by the owners. While it's true that the betterment of the league is his duty, making sure the players get the best deal possible is not.
The league is far more profitable than it has ever been. It's now a league that's watched and followed worldwide. It now has one of the most watched sporting events in the country. It has one of the best television contracts it's ever had. His deal with the Olympics has skyrocketed hockey back to the top spot at the Winter Games. Even the Frozen Four has been riding the coattails of the NHL lately and gaining popularity through them. When you know what his job duties are, he's done an exceptional job.