Great points. To me though, “versatility” means being able to use it in a wide range of hunting situations. So, if it’s not legal in the places I hunt or there isn’t a bullet available for it that is ideal for a given target animal, then I consider it less versatile.
Let’s leave predators out for a moment because if you’re saving the pelt, there’s no muzzy made that’s what we would call “fur friendly.” So if I’m shooting a predator with a muzzy, I’m not planning to save the hide. I use my .204 Ruger for that (leaves one .204” entry hole).
So for big game, my first questions are always, “What species am I hunting?” and “at what range do I want to be able to shoot it?” I think a .40 would be fine for most deer-sized game, but if I’m hunting elk, brown bear or moose, for example, at ranges of 50-100 yards average, I want a heavy controlled-expansion bullet. I don’t know of any .40s that really fit that bill. Don’t get me wrong, I’m intrigued by the .40 as well but, there’s no doubt in my mind it’s not as versatile as a .45 or .50. With a smokeless-capable .50 really being the most versatile of any muzzy out there, IMO.
Bullet selection for the .40 is very limited - Fury, Parker, Pittman and maybe Northern Precision make a couple, but they are mostly target or thin-skinned game bullets IMO. I think that will change with more of us buying .40s, but right now, there’s a lot of hunting that I do, that I couldn’t do with a .40. Terminal performance is not all about speed or energy.