You took the two BEST calibers in two different formats, and are trying to compare them. Apples & Mangos. If you prefer revolvers, shoot the 357 magnum. If you prefer semi-auto, go with the 45acp. Other factors:
1) There is no such thing as "Stopping Power" with a hand gun. Especially among calibers. A 22LR between the eyes will probably "STOP" the person on contact.
2) The objective to shooting someone, is to STOP them from harming you. That doesn't mean the person being shot has to die; just simply STOP harming you.
3) The larger the caliber, the bigger the hole going in. Thereby the POTENTIAL for more tissue damage and blood loss.
4) What the bullet does once it being entering a person, will determine if "ADDITIONAL" damage can be achieved. I.e. if the bullet EXPANDS, as in a Hollow Point, then you have a larger object internally, causing more damage.
5) A 357 at max expansion, can not be larger than a 45 at max expansion. It's not physically possible, assuming both bullets expand as intended. Therefor, the 45 will have a larger area to cause potentially more damage.
6) The area whereby the 357 magnum become more effective over a 45acp, is the one area that most people DON'T want to happen. Because of it's velocity, a 357 can penetrate more than the 45acp. To the point where it's possible to exit the body. At which point, you have the "Effect" of 2 bullet holes and twice the potential for blood loss; reduction in blood pressure; and thus loss of consciousness. But you also risk the possibility of accidental contact with another person once the bullet exits.
7) If not using full load 357 magnum ammo, and instead are using less velocity, 38spl or 38spl+P; which many people do; then the argument is totally moot, because then you aren't actually shooting a 357 magnum anyway.