... guys who have used the .357 Magnum and found it lacking.
I'd say that's quite a few assumptions and arrogance on your part.
I'd say the arrogance and assumption is with those people who find the CARTRIDGE lacking. Because, simply, its not "lacking" anything.
Is it the ideal round for certain situations? no. Does it kill deer? absolutely yes. If there is anything "lacking", its on the part of the shooter, NOT the cartridge.
Whether its lacking judgement to use the round within its effective envelope, or lacking the skill to make the needed shot, the fault is the shooters, not the round.
Don't take the failure of a head shot as gospel, either. Head shots are where Murphy loves to play games. A shot that would ordinarily punch right through CAN fail to do so, and even just glance off leaving a superficial wound, IF the stars line up just right. And, its not the thickness of the skull, its the exact angle and curvature where the bullet hits.
I once saw a guy shoot a skunk 3 times with a .357 Magnum (Marlin carbine), using 158gr hard lead SWCs. Didn't stop the skunk. Should we conclude from this that the .357 is a bad round that won't even stop a skunk? Some would, it seems.
On the other hand, being there, and seeing that each shot was a bad shot, all went in "aft of the boiler room", they did exactly what they were built to do, sailed right through the guts without doing anything else. I wound up dispatching the skunk with a single shot from a .45 Colt. Also a hard cast SWC, but it worked perfectly, because it went in the front of the head, and out the back, ending the skunk's misery.
USE the right bullet for your target, and put it in the right place, and it works. .357 is touted for how well it works as a manstopper. If it stops a man, it stops a deer. You might be better off choosing one kind of bullet for one kind of target and another for another, but the round has the capability, its up to the shooter to use it properly.