Put Captain Solo in the Cargo Hold said:
I like Bingo's plot, but regarding the "real" Vader, why would Anakin take his name? Also, such scenario risks diminishing the reveal's impact because some could assume Vader is the one who lies. But then things on the screen take different results than on paper, so I can't say for sure.
Guilt would be the prime motivator.
Guilt at being chosen over the hero of the hour, guilt at not being able to save Vader's mother, not to mention the freak out moment when Vader's dying mum confuses him with her son.
When Real Vader is believed killed Anakin sees his guilt in the form of the giant dark shadowy Darth Vader doing terrible things he can not prevent, but really this is himself.
Once he awakens to the fact that the real Vader is dead, it's too late to save Anakin (burnt to a crisp, his order shamed and hounded, his friend and mentor has permanently disabled him and left him for dead, his wife has abandoned him and taken his child) so he becomes Vader. His suppressed Id becomes his new Ego.
In the PT as it currently exists we have someone who consciously does terrible things (like killing children) and still bitches about getting overlooked for a promotion, and we are meant to feel sympathy for this guy? He is the guy who can be redeemed by throwing the old man down a well?
If he did those things while suffering a genuine mental illness it's possible to feel sympathy for him and even forgive him because he isn't totally responsible.
If he therapeutically dressed up like Doctor Doom and strangled underachieving co-workers, that would require some redemptive act to compensate.
As for believing that Vader is lying while watching the ESB reveal, I was a ten years old in 1980 I can assure you back then a large number of us were convinced Vader was messing with Luke's mind.
It wasn't until ROTJ that we knew for sure so if that scenario works on that level it's doing it's job.