As much as I would wish it different, none of your logical suggestions will have anything to do with what round NATO, may or may not choose as a replacement for the 9x19mm. The decision will be about money and who is going to make it. The different arguments made here will be part of the excuse for change, not the reason for change. The people arguing for a new handgun round will be the ones not currently making the money that the current winners are making now. That means a lot more for than against.
Remember that statement, "let's make a deal".
Colt M1911, AR-15 | S&W Model 19, Model 27| SIG P238 | Berreta 85B Cheetah | Ruger Blackhawk .357MAG, Bearcat "Shopkeeper" .22LR| Remington Marine Magnum SP 12GA., Model 700 SPS .223