How's this for radical: Have an actor play maul to be greenscreened into AOTC and ROTS. In AOTC Maul replaces Dooku and is the main antagonist of all 3 films but is never referred to as "Darth Maul" but always as "Darth Vader". In ROTS, everything culminates on mustafar as before, but with Obi Wan and Anakin both going together to face off against "Vader". The duel commences as before but ends on the thing sinking into the lava. Obi Wan force jumps to safety, but Anakin and Vader both are too late and fall over the lava waterfall together. We would then move the scene where Obi-Wan looks at the security hologram more toward the end of the film, after the duel, but heavily edited. It plays out as before with Yoda "If into the security holograms you go only pain will you find" and whatnot and Obi-Wan's response saying he has to know the truth. But we never see what Obi-Wan sees in the hologram; just him with a shocked expression saying "it can't be. it can't be."
What this does is make it so we aren't confused as hell later during Ben's speech in ROTJ. It all makes sense. When he explains everything suddenly we as an audience know what he saw in the hologram. Anakin turning to the dark side. They both went over, but only Anakin survived. He BECAME Darth Vader, literally taking over the life of his predecessor. But before the reveal we assume that Maul/Vader survived and was pimped out with the robotics and suit to keep him alive.
I have always hated the ideas and edits that simply remove anakin turning altogether or make it seem as though he died on Mustafar. It still makes Obi-Wan seem like a lying asshole in ANH and diminishes greatly the surprise in ESB and honestly I feel it completely fails in it's sole purpose of preserving that reveal. My way you don't feel like Obi-Wan is a lying asshole, the reveal is preserved and actually enhanced because you are presented a mystery of what Obi-Wan saw in the security hologram, and you are given clues and suspicion. This mystery is only completely answered in ROTJ. The only problem I can think of would be explaining how Obi-Wan got Anakin's lightsaber to give to Luke.