The new ability to rebrand teams in Franchise was a big step in the right direction. If we could add to that the ability to change the number of teams and divisions and/or leagues (as exists in on-line custom leagues) that would make it even better, especially for those creating historical teams and leagues. I recognize it might be challenging generating schedules for leagues of differing numbers of teams, but that should be doable.
Perhaps this can be added to MLB 21 The Show.