The biggest problem with MLS is the lack of competitive academy systems like those that are pervasive in Europe.
This isn't an academy structure problem for soccer/football, as there different ways to reach elite level of playing.
The issue is Americans just don't seem to be interested in soccer. IMO What the US lacks is many tiered leagues like the British have (maybe others).
They need small towns, perhaps start on the west and east coast to have small teams, not affiliated with the MLS, but could still be loaned players. Get locals involved in the sport, futsal leagues.
Minor league baseball suffers because as soon as a someone gets good enough they move him up, within the season. After many seasons the players have no where to go? Well they can find a small team to pay them part time to play.
The multi-tiered system would have relegation and promotion to move up or down in the league. This give incentive for fans to root for their team to get to the next level to watch better players in general.
TL;DR America needs soccer fans, thats the only way any of they get better, and then young athletes will naturally enter that sport as opposed to the University system that exists today, where its 4yrs and done, or Football/Baseball/Basketball.
