Regarding the Big Sky tourney, I'm not sure how well a neutral site would work given the expansive geography of the league. I think it works well with the current format. Additionally, basketball is, at best, the #2 sport at every single Big Sky school except for Weber. By comparison, basketball is the #1 sport at every single Summit school except for NDSU and now Denver. So a comparison between the emphasis placed on the conference tournament in each league is really apples to oranges.
The Summit has a good thing going with its set up in Sioux Falls. In the case of Big Sky basketball, the best attendance numbers are going to come when the tournament is held at the site of the regular season champion, even if that means short notice. I think it is more likely to draw 6,000+ in Ogden or Missoula, perhaps even Grand Forks one day, on a week's notice than it is to expect fans to buy tix in advance in good faith if it were held at a neutral site like Las Vegas, Denver, or Phoenix.