Good player handling code doesn't just translate the player's inputs into action, it tries to discern the player's intent.

Well put. This is what separates the good user interfaces from the bad.

For example, you're building a mouse-based or touch-based interface for editing a Bezier spline for a a program like Flash, Illustrator or Corel Draw. A bad interface would have the user precisely hit the control points with the mouse or finger. A good interface would expand the hit testing zone of each control point to a circle several pixels wide. A great interface will detect situations when the user hits multiple hitzones, and select the nearest control point (so the hitzone pattern for a set of points close to each other becomes a Voronoi diagram).

Another example of this is the angle of escape in pulldown menus:
http://thomaspark.me/2011/10/making-menus-escapable/