There are plenty enough baseball players to support it - and giving more fans baseball is good.
If I were baseball el jeffe, it'd be:
four 8-team divisions ... 12 games in division, 9 out of division, 6 interleague (one opponent home and home, the natural rivals can stay that way and the rest can rotate)
Two division winners get byes, the best four of the rest play a wild card round.
The geographic alignment still matters as long as fans consume television across 4 time zones.