(A purely hypothetical one, of course.)
Have every team play every other team 6 times a season, 3 home/3 away. That’s 174 games. Make it a 30 week season (including a full week for the All-Star Break) so every team has an off day Monday or Thursday of every week. If you start this in the last week of March, you end in mid-October. And of course we are shortening the postseason to make this work. It’s back to the old days of just a World Series between the teams with the best record in each league.
Even though the regular season is longer, it is easier on the players with the longer All-Star Break and a day off every week.
The shrinking playoffs decreases revenue, and this is the reason why these exercises are purely hypothetical, but the six extra home games would help with that.
The leagues remain in place mostly as a formality and excuse to play the World Series since the schedule is exactly the same for every team. So even the pennants would not be very meaningful, even though the regular season would take on prominence.
Basically, the team with the best record in all baseball would be the “real” champion of the season, but the other league gets a shot at beating them for bragging rights.
None of it is perfect, but I think I would like this setup better than the current one.