Like others have said, the commissioner is just a fugurehead for the owners, so radical change has to come from new blood in the owner’s ranks rather than one guy.
I think MLB owners are just as reactionary as NHL owners when it comes to improving the game. I like the concept of a pitch clock and robo umps and think that there are rules that could be implemented that make the game more enjoyable without sacrificing the history and integrity of the game but the implementation of everything thus far sucks.
I think the ideal commissioner would be someone who understands the fan perspective. The number one priority should be removal of the stupid blackout rules, baseball wants people to watch, advertisers want to pay to be seen by more eyes, make it happen!