How many teams should MLS have?

Major League Soccer has announced its 18th franchise, Portland.

The quality of play in the MLS leaves a lot to be desired -- the best players in the world will want to play in Europe, where they can make much more money and play against the best players. But I think that the quality of MLS can be improved, by hiring quality managers (basically the 'head coach' position), and by taking advantage of the expanding talent base in the United States, as soccer becomes more popular.

I can envision the MLS eventually capping out with thirty teams, divided into three divisions. Every team would play every team in their division twice per season plus every other team once, for a total of 38 games per season, which is quite reasonable for a soccer season. Then for the MLS cup tourney there can be wild-card games and so forth.

Regardless, I would like to see soccer return to the southeast (especially Florida). Plus I believe St. Louis and Montreal should join the league.