Remember they wanted to dissolve two teams before the 2002 season? The rumored targets were the Montreal Expos and Minnesota Twins at that time. Yep, too many small markets struggle as it is.
Unless they want to go to international expansion, it’s hard to think of too many large American cities which are solid markets for expansion.
Las Vegas is the largest market without pro sports, but the leagues are concerned about legalized gambling on sports there.
Otherwise, you’re down to smaller cities such as Portland, San Antonio, Oklahoma City, New Orleans, Columbus, Charlotte, Indianapolis as major league baseball expansion sites. Even if the fans solidly support teams in these cities, you would just be adding that many more small markets to baseball by expanding, which would magnify all of the existing problems.
Vegas will never be able to support a team. It’s too much of a population island since there isn’t enough population in the rest of the state to bring in consistent crowds. Apart from SLC, the larger cities within a reasonable driving distance have their own teams.
Even their minor league baseball team has trouble drawing more than a couple thousand people.
My suggestion is keep 14 and 16 teams, but make each league a little different. Divide the NL into four four-team divisions with no wildcard. The AL gets two seven-team divisions with two wildcards.
This gets rid of the AL West and NL Central issues and gives the two leagues different personalities. The AL has the DH and wildcard teams, the NL has a more pure race for division championships.
Nashville has been pretty good at supporting NFL and NHL franchises.