Let's peek ahead to see where the 2016 tournament will be played, and if we can glean some useful nuggets from it. There's usually a built-in geographic advantage or disadvantage for a few teams, just based on luck of the draw.
First and second round sites:
Thursday/Saturday sites: Providence (hosted by Providence), Des Moines (hosted by Iowa St), Raleigh (hosted by NC State), Denver (hosted by the Mountain West)
Friday/Sunday sites: Brooklyn (hosted by the A-10), St Louis (hosted by the MVC), Oklahoma City (hosted by the Big 12), Spokane (somehow hosted by Idaho. What?)
Yeah, Idaho is the host site for an arena. Which is in Washington State. You figure that one out. The other 3 programs hosting sites might get hurt a bit (Providence can still wind up in Brooklyn, Iowa St in St Louis, and NC State....is gonna have to travel).
You'll notice the southernmost sites are really in Raleigh and Oklahoma City. The southeastern-based programs (looking at you, SEC), might be in for a bit of a hurt, especially once you consider that UNC and Duke are going to want to play in Raleigh. You'll also notice a void in the southwest, with no regionals in California, and the two western regionals being north in Spokane and mountainous in Denver.
The geographic cluster happens in the plains, with Des Moines, St Louis, and Oklahoma City. Expect OKC to house the best of the Big 12. The best of the Big 10 will likely funnel to Des Moines/St Louis (with the obvious exception of Maryland).
All these notable things aside, however, the geography is rather balanced. You have 3 east coast regional sites to house your east coast teams, 3 midwestern sites to house all those teams, and 2 west coast sites that should be good enough to cover all the best west coast teams. Reasonably balanced.
Regional final sites:
Thursday/Saturday: Anaheim (hosted by the Big West), Louisville (hosted by Louisville)
Friday/Sunday: Chicago (hosted by the Big 10), Philadelphia (hosted by LaSalle)
For Louisville, at least Chicago isn't that far away, so not the biggest deal. Again, notice the lack of southern options in general. The ACC frontrunners and Maryland will have 2 reasonably close sites in Louisville and Philly to choose from. Other Big 10 favorites have Chicago to gun for. Pac 12 favorites have Anaheim to go for. Big 12 frontrunners will have to travel a bit, though. And Kentucky has an in-state option.