I really, truly hope that there are another 4-8 teams announced before the start of the season. There are too many talented players in the game to only field 10 teams. If there are only 10 teams, even if each team has 4 substitutes, that's only 100 players. IMO there are easily 200-300 "pros" that deserve to make a living in this game.
Teams I'd love to see:
Melbourne/Sydney
Tokyo
Additional Korean teams (multiple LA teams means we could see multiple Seoul teams)
Seattle
Chicago
Paris
Berlin
Rio