Anakin Skywalker is not Darth Vader. Darth Vader killed Luke Skywalker’s father. If (and I do mean if) Luke’s father was named “Anakin”, that Anakin died years before the events in Star Wars (not “Episode whatever” — just Star Wars).
Anakin Skywalker is just some asshole in a Darth Vader costume.
And “Darth” is not a title. “Darth” is Darth Vader’s first name. It’s no more a title than “Luke” is. When Obi-Wan met Darth Vader for the last time on the Death Star, he didn’t call him “Anakin”, or “Lord Vader” — he called him “Darth”, because they were friends once, and that’s the name Obi-Wan knew him by. He called him by his first name because they were on first-name basis.
Pretty much every major plot point introduced after the original Star Wars is inane. Luke is Lleia’s brother? Inane. Darth Vader is Luke’s father? Inane. Darth Vader built C-3PO? Are you kidding me? Why not make Obi-Wan into Chewbacca’s father and Han Solo into R2-D2’s long lost twin, while we’re at it? Or wait: Obi-Wan could be Lando Calrissian in disguise (or vice versa)! You never see them both at the same time….
When Highlander 2 came out, revealing that immortals all come from the planet Zeist, Highlander fans were smart enough to realize that this was ridiculous, and they rejected it. If only Star Wars fans were that intelligent. If only George Lucas were that intelligent.
The Star Wars franchise started great, and got worse with each sequel. It has a lot in common with the Planet Of The Apes franchise, although of course Planet Of The Apes is relatively free of the pretentious bullshit that has accrued around the Star Wars franchise like so much guano.