Here's a controversial idea: with better adjacent channel rejection of modern radios, repack the band so the metro market stations are separated by 3 channels instead of 4.
I'm guessing the reason it's a non-starter is the second adjacent relationship between markets that are 65 or 75 miles apart. Denver vs. Colorado Springs/Pueblo that co-exist and interleave nicely now would be on opposite ends of the band. Without IBM's Watson to run a new Table, I'm guessing 3rd adjacent spacing would mean fewer stations instead of more.
I'm guessing the reason it's a non-starter is the second adjacent relationship between markets that are 65 or 75 miles apart. Denver vs. Colorado Springs/Pueblo that co-exist and interleave nicely now would be on opposite ends of the band. Without IBM's Watson to run a new Table, I'm guessing 3rd adjacent spacing would mean fewer stations instead of more.