The single-action, straight pull, non-hinged trigger.
Whether or not a crisp, tunable, potentially nearly creep free trigger is necessary or desirable is up for grabs but if one decides it's a personal priority it will be difficult to match with alternative designs.
Some 1911 folks, if asked the five most important reasons they favor the platform, will list "trigger" all five times. It's a mechanical issue. Some may prefer the "feel" of the SAO non-hinged trigger but, if so, it's related to a strictly mechanical, or "technical" if you will, property of the design.