The movement did stand out to me, but I found it added to the atmosphere. It's a robot, its movements are supposed to be unlike that of humans. The non-physics based aspects just add to the mystique of the story for me, as this is clearly set in some (dystopian or not, for the viewer to decide) future. 3-CPO also walks 'weird' or at the very least unexplained from a physics/mechanical pov, but its movement is iconic nonetheless.