Controlled penetration is one of the exact reasons I carry .45 ACP. I
want it to stop. In the target - not go though it and kill the innocent bystander 1/2 a block away. (And yes, I realize you should do your best to ensure the area behind your target is clear, but when bullets start flying, you don't always have the luxury.)
As you said ".45 puts a big hole in stuff" - the stuff I'm aiming at, not the stuff behind it. Wound cavity size is what does the damage and gives a firearm it's killing power. I don't want a through and through wound. I want the round to hit, expand and do as much damage to the
intended target as possible without coming out the back side.
Due to the mass of a .45 round, there's not much chance of clothing stopping it, but it's low speed makes over-penetration a lot less likely. Still possible, but less likely.
With that said,
any round is dangerous. Anyone who says any differently is being very naive.
I've just never liked 9mm, but that's a preference. Either one is a decent self defense round when it comes down to it.
And I still stand by the axiom that the absolute best gunfight is the one you managed to avoid altogether.