The USOC needs to find a way to bring back
Cal FC to make the tournament more interesting for Timbers fans!
But seriously, it's true that if amateur teams don't upset the usual NASL/USL crowd, the draw can get a little stale due to regionalization of the draw. I feel like the Revs have played Rochester or Harrisburg a million times, though we've played the Carolina teams and Richmond a few times too.
Of course, the little guys don't want to have to fund a plane trip somewhere and MLS teams are happy to skip a cross-country midweek road trip. Regionalization isn't going anywhere, but more expansion could make it a bit better.
It can get even more stale on the West Coast, where was a period of really weak minor league presence after the departure of Seattle, Portland, and Vancouver. The USOC tries to set it up so that the first round is all amateurs and the second round has amateur vs. minor league pro games. The numbers don't exactly match up and the west usually gets a few amateur vs. amateur games due to the paucity of minor league teams.
Since the NASL was founded in 2011, there hasn't been a single West Coast team until the San Francisco Deltas launched this year...and there aren't many reasons to feel great about that club's staying power.
The USL added:
2011: LA Blues (now Orange County SC)
2013: Phoenix (not West Coast, but take what you can get)
2014: Sacramento, LA Galaxy II
2015: Sounders 2, Timbers 2, Whitecaps 2
2017: Reno (not really West Coast, but close enough in terms of travel)
Reserve teams can't play in USOC so that's not much to work with.
NASL has announced teams in Orange County and San Diego next year. There are rumors that USL is going to Fresno and Boise. It'd be nice to fill out the map a bit more, but there just aren't as many markets out there. Bakersfield is reasonably big. Someone could try to make it work in Oakland. I'd love to see someone try to do something in the Inland Empire.
Getting increasingly farther away from the coast, there's Las Vegas, Tucson, Albuquerque, and El Paso. That's about it, unless one of the proposed new D3 leagues gets off the ground and finds a model to make pro soccer work in significantly smaller metros than what's currently found in the USL. Then you could, in theory, eventually make a local division with a similar footprint to the California League.