I'm in favor of that structure. Very good odds for the Mets in that division. Make it happen MLB.
When they expand to 32 teams (not if, I think expansion is a given) there is a much better chance of re-alignment within the same Leagues. There is a precedent for that with the 1994 re-alignment and creation of the Wild Card. That was certainly a big change, but the AL/NL were shuffled a little bit to make the 3rd division. I just can't see the owners voting to disintegrate the 2 leagues that have existed since pre-1900 with the NL and 1901 with the AL. I'd bet on a re-alignment within the leagues. Maybe something like this:
NL East: Reds, Nationals, Braves, Marlins
NL West: Padres, Dodgers, Giants, D-Backs
NL Central: Rockies, Brewers, Cubs, Cardinals
NL North: Montreal (EXP), Mets, Pirates, Phillies
AL West: Portland (EXP), Mariners, Angels, A's
AL South: Royals, Rays , Rangers, Astros
AL Central: White Sox, Tigers, Indians, Twins
AL North: Blue Jays, Yankees, Red Sox, Orioles
I think this works fairly well. It keeps all the BIG rivalries together (LA/SF, NYY/BOS, CHC/STL). It does make for a couple weird divisions like the AL South with teams from 3 different divisions combining. But if you look at the map, the AL South is the only team that has super large travel distances.
With this, I would give each division winner an automatic playoff spot and continue have two wild cards just like the NFL. Top two teams in the league get a bye in the first round.
I really just don't think the leagues will be disbanded.
Although I wonder if they woukd split up crosstown rivals. Pittsburgh and Philly. 1 in the east, other in the north.