Might as well outline my concept for preserving the reveal in Empire while still providing a story with a beginning, middle, and end, not making Ben sound like a liar, and not making the audience feel like they’re missing information (even though they are).
The idea is that there is a new character named Darth Vader (Name. Not title.). In Episode 1 Vader is a young Jedi apprenticed by Obi-Wan (and I guess Qui-Gon if you really want him there). Feeling insulted by the Jedi for ignoring his talents and potential by pairing him with such a young, inexperienced Jedi like Obi-Wan, he joins the dark side, staging his own death at the beginning of the film, only to reveal himself as the one behind it all toward the end. (If Qui-Gon is there he can be the one to kill him, adding more personal rivalry between he and Obi-Wan.)
Obi-Wan meets Anakin, takes it upon himself to train him as a Jedi, yadeeyada. Eventually, Anakin’s pushing of himself and lust for power turns him to the dark side, teaming up with Darth, his enemy, but Palpatine the puppet master’s plan is to pit them against each other for the more powerful one to be his ultimate apprentice.
Everything leads to a three way duel between Obi-Wan Kenobi, Anakin Skywalker, and Darth Vader atop a massive volcano. Obi-Wan get tossed aside and topples down the side of the volano. Miraculously he survives and watches in horror from a distance as his greatest enemy and his former best friend duke it out atop the volcano.
Both of their lightsabers get tossed aside. They struggle with each other physically. The volcano trembles as the two let out their anger. They push and pull at each other ferociously until they both topple over, disappearing into the fires of the volcano.
Obi-Wan assumes them both dead and leaves, taking Anakin’s saber as a memento of his fallen friend.
Much later we cut back to the edge of the volcano where a charred hand reaches out from the volcano and grasps Vader’s saber lying in the rubble.
Fast forward to A New Hope. Obi-Wan says: “A young Jedi named Darth Vader who was a pupil of mine until he turned evil helped the empire hunt down and destroy the Jedi Knights.” Check.
“He betrayed and murdered your father” Check.
You may feel like Obi-Wan is withholding some information to spare Luke’s feelings, maybe hoping to tell him the whole story later, but you never get the sense that he is outright lying to Luke.
Fast forward to The Empire Strikes Back: “Obi-Wan never told you what happened to your father.” You’re thinking ‘he’s going to tell Luke that Anakin turned to the dark side before he died to convince Luke to join him’
Then he drops the bomb “No. I am your father.” Suddenly it makes sense. Anakin is the one who crawled out of the volcano, not Darth. Anakin emerged and took over the mantle of Darth Vader, leaving the last trace of his old identity behind him.