I don’t see how the “finding the secret to prevent death” is nonsense considering mortality is a big theme to the films. Force ghosts? “I’ve become more powerful then you can possibly imagine?”. Luke saying to Yoda that he can’t die and Yoda responding that that is the way of things?
I can’t speak for Mocata, Screams In The Void or others. For me it was nonsense because it was so poorly executed and poorly shown in ROTS, and I believe there were other better ways to have Anakin fall to the dark side. You think so too in creating this thread and your opening post: “Anakin’s turn to the dark side wasn’t structured the best in the Prequels.”
As Lucas said, the epitome of greed is the desire to cheat death. The Sith are defined by being greedy and selfish. There’s nothing more greedy then wanting to take away a fundamental aspect of the nature of living things because you can’t accept the natural course of life. Therefore, it makes sense that the ultimate goal of the Sith is immortality. And as I said in another thread, having Anakin’s turn be about cheating death creates a nice retroactive arc when Vader accepts his death in ROTJ (“Nothing can stop that now”).
I do not care too much for what Lucas said later, because if he needs to explain things afterwards he likely did not do a good job explaining them on screen at the time. Lucas is also not a reliable person to listen to so I do not take his words seriously as some others do, even as the creative genius behind all of this. I do like to listen to creatives talk about their work and intentions, what worked and what didn’t, but in the end what matters is what happens on screen.
As others say “show, don’t tell”.
But I do like reading your and everyone’s thoughts on restructuring Anakin’s turn to the dark side in the Prequels.
Spartacus01 post above is interesting and has potential too.