A New MLS Conference Possibility

With the announcement of an unbalanced schedule this year, the Eastern and Western conferences will play more purposeful roles than they have in past seasons. MLS seems to be moving away from the idea of a single table format this season. League expansion, season length, and the geographical size of the league have all been sited as reasons that a conference system is better for MLS. With that being said, what possibilities does the league have to develop towards? The league could, and probably will, stay in the East/West format that it is in currently in, but how many teams can be added before we run into season length issues again? The league could split the conferences into 2 divisions as more teams are added, but this will require the league to grow fairly large, maybe to a size that isn't sustainable. Instead, the more interesting option for league may be creating a 3 conference system.