A commish has two very separate roles. One is to be an owner just like the 31 others and do his best to win the championship. The other is to be commish. They are separate and distinct and a good commish should not let them overlap.
A bad commish will do something like this: enact a ruleof no franchise relocation, decide he cant win in his current city, and then change the rule so he can move. That's mixing your two hats up.
A good commish will stick with the league rules and will not change them. People joined his league for the rules that were put in place, not to have the rules pulled out form under them. Yes, there wil be times when rules need tochange, but a good commish will make certain any changes are discussed at length and maybe even voted on.
A good commish also will not put his own team above theleague when doing commish duties. Example: turning down a top owner because the open team is in his division and adding a newbie that he can dominate instead. that is bad for the league.
All that being said, being a commish does not take very much extra effort. Other than around rollover time when you have to recruit...and hopefully the rest of the league understands that recruiting is even a job for the entire world to help with. Don't just sit back and think one person who is in 3 or 4 worlds can magically make half a dozen new owners appear.