The end of ROTS is a perfect example of putting in plot points to appease the OT fans. If Lucas wanted to make a compelling 1-6 story, Anakin should have been left burning on Mustafar, and never seen again til he breaks down the door in ANH at the beginning. That way the whole OT you are watching it wondering who this Vader guy, holy shit, it is Anakin! He survived!!! Now there would have to be some dialogue changes in ANH by Kenobi to compliment the linear storytelling, but if Lucas truly wanted the story to be watched in 1-6 fashion, the ending of ROTS would be totally different.
Also, there are things in the PT just to appease the OT fans, cameos by Jabba, the jawas, and the tuskens in the pod race which are pointless. Owen would have had a much different role had it been written 1-6, but Lucas had to find a way to get him in so he makes him fucking own C3PO 20 years before buying him unknowingly again?
The only thing that Lucas was concerned about in the PT was Anakins character arc, and that is the only thing that he wants to succeed in the 1-6 storytelling now, as you see this little boy who is a good kid go down a dark rode to become Darth Vader and then redeem himself in ROTJ at the end of the movie. Now that is a cool story, the problem is the fucking OT only really covers that story at the end of ESB, and the last hour ROTJ! So you basically have most of ANH, half of ESB, and half of ROTJ that don't deal with Anakins character arc.