Would love to see some type of pencil update as well. Although not sure what that might be other than different tips.
An eraser? I think this would be very welcome by many users.
Better charging method? Sticking it in the end of my iPad Pro looks stupid. Keeping up with the charging adapter is stupid.
Clip? If nothing else, to prevent it from rolling!
Increased resolution, shading levels, and reduced lag? I don’t think it “needs” these, but would be good selling / marketing features.