Compactness and prohibition of county splits would help R's more in the North than it would help D's in the South, particularly with the existing VRA rules.
R's drew very favorable maps of Michigan for decades with rules like these in place.
Yeah I think you need additional checks on redistricting commissions in addition to just compactness and prohibitions on county splits, but by the same token I think those rules are needed, and should probably be weighted pretty highly. Otherwise you get higgledy-piggledy messes like Colorado where this stuff was deprioritized over very nebulous definitions of CoI.
Putting cards on the table myself, I think redistricting commissions should weigh these factors, in roughly this order:
1. Compliance with the VRA
2. Keeping metro areas whole
3. Compactness
4. Whole Counties, cities, etc.
5. Robustly defined communities of Interest--i.e. no spurious "South Colorado," type stuff. Ideally the CoIs would notable enough to have a Wikipedia page or be recognized in councils of government.
6. Minority Influence districts above and beyond the VRA.
7. Public Input--ideally this would be higher, but the incentives are too high for partisans on either side to try and game the process.
Ideally these would be sort of nested. For example, a commission which worked like this in Colorado would likely put Pueblo in the 4th district, regardless of public input, due to its obvious regional location in the High Plains, but then at the margins where things are less obvious, like where in the Front Range to get excess population from, public input could play a role.
Of course a lot of these should be tinkered with to some extent depending on the states--counties shouldn't matter in New England and only a little in Arizona, but a map which splits counties in Arkansas should probably be disfavored.
