I'm a little confused as to what your point is here.
The 357 Sig has superior ballistics and terminal effect of the 9mm, 40 S&W or 45 ACP as evidenced by those LE agencies that use the round.
This caliber gives you the magazine capacity of a .40, with the ballistic performance within the realm of some .38 super loads. Personally, I think the capacity alone on the .357 sig is discouraging enough.
But that's just me.
Here's a comparison of 9mm, .38 super, and .357sig for reference.
The data on that link for the 357 Sig is for the watered down version. Underwood is achieving over 1500 FPS in real world testing in 4" barrels with a bonded 125 grain bullet.