He became more machine than man, even his thoughts were mechanical and without heart.
That's a nifty idea & works well. I still think that having Vader not trust the Emperor (at least before he's ordered to kill luke) works against the story. The emperor is his master. He taught Vader the dark side powers. I see their relationship much the same as a relationship between a martial arts master and his student. The student doesn't follow a master/teacher who he doesn't trust/believe. I still find it to be a more powerful story for Vader to have betrayed his best friend (OB1) on order to follow an evil master who he really believed in, only to find out decades later that this master really IS evil, & he really DID make the wrong choice. At this point, Vader has an internal struggle that mirrors his turn to the dark side in that he must once again turn on his master and defeat him. Only this time, he succeeds. (after all, OB1 did beat him down, even before the PT came about).
That's a much more dramatic tale than the story of an apprentice who never really trusted his master & always had a desire to overthrow him - there's not nearly the same internal struggle going on. & there's not the parallelism of it mirroring his original turn to the dark side. After all, recurring themes is a big part of Star Wars. In my version (or the original version, if you like....), it's a huge battle for Vader to make that decision to kill the Emperor. He's been through this once before. He trused this man & looked up to him. Now he has to make the same decision again in his turn back to the good side as he made when turning to the dark side. His actions likewise parallel in making the choice to kill his master whom he once would trust to the ends of the galaxy and back. That is just so much better than what we were given in the PT! Now Vader isn't struggling so much in ROTJ. He's just taking advantage of the opportunity to do what's he's been planning on from the get go. *yawn*. No real drama there. No internal struggle. I think i'll keep my OOT version and so "no thank you" to the "saga".