Ain't nothin' wrong with plain ol' 9x19. Far more good defense loads available, even +P stuff. It loads and functions 100% in small, concealable, easy to carry handguns as well as full size service pistols. And, when you can get a box of practice ammo for under 6 bucks at Walmart, why the heck would you care about a handgun game playing load like 9x23? If you want .357 ballistics out of a service pistol, get the .357 sig! Well, it's CLOSE with a 125 grain bullet, anyway.
I think too many people are reinventing the wheel in the firearms world. Been doing it for a while, I guess. The real innovation is at the top end of handgun power now days like that new .460 Smith cannon.
I think it's all pretty much been done in self defense cartridges. From the .357 magnum and .45 ACP to the .32 H&R mag/S&W long and .32ACP, I can't think of a real innovation that needs doing. Maybe I'm wrong. But, every time some "new" cartridge comes along, it just seems to be a rehash. The 10 and .40 were pretty innovative, but since then what has really set the world on fire? The .41 mag was the last I can remember before the 10 came along and it was the answer to a question that didn't need asking. The .357 is a better defense round. If the .41 had caught on, there might be more suitable loads available for it, but it's pretty dead as a defense load, though more of by hunters.
Before the .357 sig and the 9x23 and whatever else, there was the .38 super. It's basically just a hot rod 9x19, same ol' same ol'.