So is his argument that hypothetically if there were a 50-50 race in New Jersey, the Democratic map would be fairer than the Republican one? This shouldn't fly, because while that is a fair thing to consider, the map could then be unfair at the realistic levels of partisan support for elections in New Jersey. Proportionality should be part of partisan fairness too, so that voters of the opposite party in safe states are not under-represented.
No, proportionality is an absurd criterion to apply to SMD maps, which when enforced tends to lead to objectively awful maps. Didn't we go over this in another thread recently?