Lucas didn't develop the friendship enough 'PRE-ROTS', however, once we got to the film I think he did the best job he could putting emotion into the fight. I ran ROTS at my movie theater, so I saw it upwards of 50 times, and everytime Anakin looks up that ramp to see Obi Wan standing there, I still got goosebumps. Lucas did well conveying the betrayal and the emotion in that fight.

But you are right, up until the last film, he stuck too closely to an ObiWan/QuiGonn style relationship when it would have benefited from a Han/Luke relationship.