This is an excellent idea (especially adding back Montreal...otherwise I'd pick Charlotte before Nashville ?) but I think you run into the same problem with the Midwest division. I don't think it's a popular opinion, but I'd probably prefer to see all the divisions (regions of the country) represented on a regular basis than strictly the "best" teams which are probably the teams that are based in financially-sound, more appealing (for whatever reason...weather, money, things the midwest can't offer) markets. I think a salary cap begins to address that. It's an "owner-friendly" term but I bet it would be better for the sport and could be balanced out with a million different concessions to give to the players union. I tend to think arbitration and delayed free agency is the big thing for the players union to go after.
My thinking is that this regional disparity exists more in the MLB than in other American pro leagues. I only watch basketball aside from baseball, but the financial parity in the NBA is pretty great (even if the product gets worse year by year) and the incentives given to players to re-sign long term with their small market team are unmatched by other leagues as far as I know. Look no further than how the Nuggets perform relative to the Rockies. Prudent drafting and trading (good management) won them a championship because they were able to pay more than big market teams to keep Jokic and their other free agents around -- while still being able to go out and sign effective players with limited cap space. The Nuggets won because Jokic is an all-time great but you also have to give a lot of credit to the organization for finding him in the second round and then building an effective team around him, despite injuries. The Bulls and Nuggets made similar trades around the same time with the Magic for their big time pieces and the Nuggets got their championship starter for scraps while the Bulls mortgaged their future for a guy who simply wasn't good enough (even if I like Vucevic). I think you see in the NBA that you can get lucky and win by having the #1 pick in a strong draft or you can build a contender through effective management. Either way, the parameters are pretty much the same for each team. If an NBA owner wants to act like John Fisher or Robert Nutting, the salary floor means he has to pay up regardless. Then the matter of a 'cheap' owner vs a regular one becomes a matter of if they're willing to pay the luxury tax rather than if they're willing to fill out the major league roster with MLB-caliber players.
In an MLB-type environment, Jokic is probably playing for the Knicks or Lakers. The Knicks should be like the Yankees but they're constantly mismanaged and are constantly bad; as it should be. The NBA's financial system seems to work pretty well, but it's not one-to-one because one player in basketball can be the difference maker between a struggling team and a championship contender. Still, the best teams tend to perform well regardless of where they're based. Watch for Oklahoma City and Utah to be championship contenders for years to come
This post became sort of rambly and off-topic, but I guess it lends credence to the fact that the Sox are a lot worse consistently than they ought to be. Under the current framework of the MLB, there's basically no excuse for a Chicago team to be outperformed by all these other rustbelt cities in the division. It's doubly true for the Cubs, the team that the majority actually likes, but they won a WS recently so they get a break.