Sasha, Great Effort!
Couple of thoughts.....it's pretty clear that Region 2 is a hard one to get the numbers up. I would consider adding the Dakotas (and Alaska?) to them as well. Perhaps send Kansas and Nebraska to Region 4 to be more geographically consistent? Pennsylvania seems misplaced in Region 6. Perhaps swap them to Region 7 and New Jersey and Connecticut to Region 6? Region 8 is now light in numbers but future population growth could diminish that somewhat although slotting Tennessee back into Region 8 cures that, but that then underweights Region 5.
Great thoughts, GymDad9.9 thanks for the thoughtwork!
I struggled with what to do with the Dakotas, too (I kept moving them back and forth). Ultimately, I went with balancing number of states per region and geographic area (as Region 2 is already hugest geographically for travel, and flights are $$$ with comparatively smaller cities in this region). Also Region 2 population is expanding as people leave some of the coastal regions. Some growth area there is perhaps ok. Maybe the Dakotans could choose
Kansas and Nebraska I also toyed with your same thoughts. The reason I put them in Region 3 is because 1) Region 4 numbers already big and 2) wanted more States with Texas region both for numbers, and just so we don't have the "Texas plus only a couple lonely tiny states" making up a region. If Texas isn't its own region (which I also thought of and could totally work), seems there should be a handful of other States in there so they have other people to compete agains (not just Texas)t. Just my reasoning. Lots of possibilities here, though. This is the hardest one to configure and make bordering states happy, imo as Texas is just so dominating.
I swapped Pennsylvania in and out several times, too! Your solution here could work equally well or better, I think.