Let the free market decide, and it is with baseball and football. That said, no, no more teams are needed, besides, I do not watch anything as I have no TV and refuse to own one.
Technically with revenue sharing the pro sports operate on a different basis. The NFL only has teams like The Browns to extend the regular season and to keep competition out. Of the 32 NFL teams probably 8 of them would go bankrupt if not for league backing. We could then have a real free market in sports.