While many enhancements do improve the shoot ability of the 1911, they are most beneficial in competition, with hundreds of rounds fired while timed.
Actual defense use rarely requires even one magazine change, and the comfortable beaver-tail is not as important. I am a small guy, 72, and find it odd that people have trouble carrying a properly holstered 1911 because it's too heavy. A plastic 9mm weighing a few ounces less is generally easier to shoot, because they launch ammunition that is roughly 30% less effective than the .45 with heavy loads.