Grant expansion franchises to Charlotte, Louisville, Mexico City, Montreal, Nashville, New Orleans, Norfolk, Oklahoma City, Portland, Salt Lake City, San Antonio and Vancouver. Relocate the Athletics from Oakland to Sacramento, the Rays from Tampa Bay to Orlando, and the White Sox to Indianapolis, because Chicago is and always will be a Cubs town. Then realign into 7 divisions of 6 teams each, no more American or National Leagues, just 1 Major League, and no conferences either.
Northeast Division: Cincinnati, Cleveland, Detroit, Montreal, Pittsburgh and Toronto.
Southeast Division: Atlanta, Charlotte, Miami, Nashville, Norfolk and Orlando.
Central Division: Chicago, Indianapolis, Louisville, Milwaukee, Minnesota and Saint Louis.
Southwest Division: Houston, Mexico City, New Orleans, Oklahoma City, San Antonio and Texas.
Northwest Division: Colorado, Kansas City, Portland, Salt Lake City, Seattle and Vancouver..
Contract the regular season to 154 games, including one 4-game home series and one 4-game road series vs. each division opponent = 40 + one 4-game series vs. 1 team from each of the other 6 divisions = 24 + one 3-game series vs. the other 30 teams = 90. Schedule the 21 coldest weather site teams on the road the 1st month of the regular season at the home of the 21 warmest weather or climate controlled locations.
Expand the post-season to 16 teams, with division winners seeded 1-7 and wild cards 8-16. Expand all 4 rounds, including the World Series, to best 5 out of 9, with a 3-4-2 format, excluding the World Series, to be played at a warm weather or climate controlled neutral site in November. Both World Series participants could potentially play 36 post-season games. Since there is no more American or National Leagues, nor conference setup, any 2 teams, even from the same division such as the Tigers and Indians, could potentially meet in the World Series.
Expand rosters to 30 players, and not just during September, but rather the entire regular season and post-season. Expand the designated hitter rule so that each manager has the use of 3 DH's per game, and they are not limited to any 3 particular positions. For example, if a team's starting pitcher that day happens to be a really good hitter, then their manager could DH for his catcher, shortstop and second baseman, or any other 3 positions for that matter.
Expand the annual 1st-year Rule 4 amateur draft to include international prospects. With 12 more MLB franchises and expanded rosters, each organization is limited to 1 Triple-A, 1 Double-A, 1 Class A and 1 Rookie League affiliates. No more Class A-Advanced or Class A-Short Season levels.