I really don't like the idea of expansion - in the sense of expanding the number of teams above 30. There are other ways MLB as a business can grow rather than just open new franchises. I would invest more in the international brand of MLB. Europe is still relatively an untapped revenue base of fans. Look at what the EPL has done by stretching its reach to the US.
If I were MLB I would work to improve the World Baseball Classic and focus on building the game in Europe/Australia. Assuming progress is made, you can work on developing international academies, tournaments, and leagues over there to make the game more global.
Keep Montreal, Charlotte, Portland, etc. vacant so that there are always options on the table when it comes to relocation. 30 teams with 8-10 playoff teams is perfect.