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.
It’s a lot easier to come up with a balanced schedule if you have 6 divisions of 5 teams each.
20 series against your own division
5 series against the opposite league, own division
20 series against the rest of your own league
That leaves 6 series.
You could do another series against your own division plus two in the opposite league, or else all 6 series in the opposite league.
The own division, opposite league play would be nicely nested during divisional play, thereby minimizing travel expenses. The odd team out in each division would play each other.
That’s....
...actually not a bad idea. Up there with shooting Bud Selig into the sun.