jd45,
The Browning HP design indeed represents design improvements over the earlier M1911.
First, Browning eliminated the grip safety (wanted by the US Ordnance Department), eliminating the occasional user failure to depress the grip safety in the firing stroke.
Second, the barrel-to-slide lockup was improved from the swinging link to a cam design. Improved breech alignment and accuracy is achieved. Takedown was also improved, and the barrel bushing elimniated.
Third, the magazine was increased to a 13 round double stack, and a magazine safety was incorporated. Unfortunately, because of the wide mag, trigger linkage had to be routed around the grip, up into the slide, and back down to the sear. Stock trigger pulls are stiff and poor.
Fourth, the overall ergonomics were improved (lower sight line, better fitting grip, almost universal acceptance by military and police)