Akton said:

Tarkin's line also evokes the singularly unique image of Vader we all once accepted as a given - that he, as far as the citizens of the Empire knew, was the last of the Jedi; the last practitioner of the Force (to whatever extent its existence was known or acknowledged); the last wielder of that mysterious and ancient "Jedi weapon" (as Palpatine called it) - the lightsaber. And his title - Dark Lord of the Sith - being some obscure honorific attached to his position in the Empire, and not an indication that he's merely a member of an ancient order of "anti-Jedi," all named Darth and all equipped with red lightsabers (even Palpatine himself - despite his clearly expressed disdain and relative unfamiliarity with that "Jedi weapon").

This—so much this. It is exactly why the prequels just don't jive with the ideas we all had in our heads about how the SW universe worked, because the way the original films were written was full of these kinds of implications, which ultimately ended up getting stomped over and contradicted to death. It's a huge part of why the prequels will never fit as a legitimate part of the Star Wars story, no matter how anyone tries to shoehorn them in there; and why we stubbornly resist all attempts to say otherwise. Vague as they were, these hints and implications formed a much cooler picture than what was later shown, and the clashing of tonal inconsistency plays a big part in what makes them so jarring, even when removed from any considerations of their overall quality.