So in order to be a good fighting pistol it has to be a .45? Sorry, but that's truly silly. A good fighting pistol has decent power, but not too much power. I subscribe to the idea that it's all about firepower. That includes the ability to rapidly keep shooting. That means high mag capacity and moderate power to keep it under control. 9mm +P is probably about perfect.
But if you are talking about sheer power and chest exploding ability, there are plenty of rounds out there that put .45 to shame. 10mm comes to mind. Oh, and it's got more mag capacity too.
That's your personal opinion; and, of course, you're entitled to it. I've had more than 50 years of pistol shooting experience (and time) in which to form this carefully tried and tested conclusion. No other pistol caliber has the highly desirable recoil characteristics of the 45 acp - None!
If you think you can outshoot me with a 9mm, or a 40, or a 357 SIG, or a 10mm, I assure you, you'll have no better luck than many others who've tried. I have often stood next to other shooters and accurately fired two or three times for every accurate single shot the person standing next to me was able to get off. In my experience, high magazine capacity means next to nothing unless you're able to rapidly and consistently hit what you aim at.
The vast majority of pistol shooters I've shot with and against did not, and do not, know how to accurately rapid fire a pistol. If someone were to try to use a 10mm against me, I guarantee I'll get off, at least, two accurate shots for every one the other guy sends my way.
The most important aspects of combat pistol shooting are (1) familiarity with your pistol, (2) ease of recoil management, (3) the ability to quickly level the barrel and/or, 'nest' the front sight, and (4) the ability to deliver accurate sustained rapid fire until the target goes down.
You can say anything you want over the internet; after all, why not, everyone does. I've got 50 years of combat pistol experience that says no handgun caliber works better than 45 acp in a gunfight. There are pistols that shoot bigger bullets; there are pistols that shoot faster bullets; there are pistols that hold more bullets; but, there isn't any pistol, anywhere, that I've ever used in my entire life which handles better than a 45 acp during CQB pistol work - Period.
Perhaps I should add that 230 grain RN/FMJ bullets are, also, a large advantage to enjoy in a pistol fight. Not politically correct, but, a large advantage nonetheless. Besides, ALL pistol bullets are capable of passing through the target; and JHP bullets are notorious for failing to stop. The shooting incidents in which JHP's have failed to either stop or continued to pass on through are legion.
I'm too old to have a head full of silly ideas. If something doesn't work you can rest assured I got rid of it many years ago. This close to God I always try to do the right thing; and, I always use what works. If you don't want to take the advice I offer, fine; that's your privilege; but, don't call me silly. If anything, I'm on the far side of serious and have been all my life.