They went to the nine because the 1911 .45 was too big for all the new female soldiers to hold or shoot well. They picked a pistol that was STILL too big for most females to hold properly, but did hurt less - on both ends.
Now they claim they want a cartridge that does more damage - and my bet is that they'll pick a pistol to fire it that is once again too fat for small hands.
If they pick a .40 S&W, the conspiracy crowd will bellow that the real reason is because every other goobermint agent from the FBI to FDA meat inspectors are armed to the teeth with .40s and a bazillion rounds of ammo. "One more step to a police state!"