You think people would get this point by now.
Well, I disagree. The assumption that everybody would know everything about the genesis of Star Wars "by now" is ridiculous. Star Wars is not American History where we start off indoctrinating school children with the explorers, pilgrims, planters, then founding fathers & presidents, etc. People find out things, especially on message boards, by asking questions. If everybody knew everything, we wouldn't have a heck of a lot to talk about. And due to the wide range in ages of people here, "getting it" takes time.
Lucas likes to play make-believe when he says he had this all-encompassing plan for all six films. In reality, he just took each film as it came. He developed the story as he wrote each film. Period.
He did have a plan, however it was in his head, which is still a plan. No one ever thought Lucas stood on the mountaintop and threw down the Star Wars scripts in stone tablets! I don't particularly care if Lucas changed the name of the 3rd stormtrooper on the left on the 4th page in the 2nd draft. The history of how Lucas came about his ideas, along with all the fake scripts on the web, is a mildly amusing sub-culture of Star Wars. But the fact remains I love what he did with those plans. In face, the one constant thing about Star Wars is change. Heck, even the movies change.
I like the fact he took it as it came to him and wasn't resigned to heeding dogmatic views, even if it was his dogma. If the ROTJ book says Owen is Ben's brother, and in the movies it's not, the movie wins, ain't too difficult. If Lucas changes his mind and decides there actually are eps. 7, 8 and 9, that's fine too. I can deal with it.
So in Lucas' land of Make Believe, Darth is a title. In reality it was a really great marketing ploy used to enhance a rather two dimensional character in Episode 1, Darth Maul.....because Darth means Badass.
...And there's something wrong with being a great marketing ploy? Darth Maul was a fine villain, not one of a lot of consequence, but not all villains are as deep as Vader in the continuum of villainy. There was a KMC poll a while back and Mr. Maul won Best Secondary Villain. Darth being "just a title" just ain't so, because when we found out about this title, it added dimension to Vader's name unknown before. And that's cool too.