Anchorhead said:

It makes no sense what so ever that he's suddenly elevated to the feared-by-all status in the following film. What (in-story) warranted that transformation?

Exactly. This was kind of the first slip-up, where Lucas started showing a lack of understanding of the world he had created. This is one of the instances I can somewhat forgive, however, because in the end it does serve the story well. But when Lucas got around to the prequels, he suddenly had this preconception that Anakin needed to "live up" to the name of Vader. And that resulted in all this nonsense about a prophecy, a chosen one, and that Anakin's fate was somehow tied to the fate of the galaxy. He didn't understand that just like Luke becoming a Jedi in the original trilogy, Anakin's fall to the darkside should have been auxiliary to the story.

CO said:

But I will also say that the SW movies would have gotten redundant if he just made them standalone stories like Indiana Jones movies, and no real overall plot line. That's why I say every great franchise gets to a point where there is nothing more to tell, and the stories are just catering to the fanboys.

I definitely agree, and I didn't mean to imply that they should be standalone stories. I actually like the plot that runs through the OT. Although I think ROTJ could have been handled a little bit differently, I have no issue with the fact that Luke and Vader remained the main protagonist/antagonist up until the end. Their intertwined fate gave the relatively small scale events of ANH new meaning, and that's one of the things I enjoyed about it. What I intended to convey was that Anakin's fall to the dark side didn't need to be the sole focus of the story, and it didn't need to be so closely tied to the fate of the galaxy.