Technically he should look like Vader, armor and all. That’s a hill I will die on.
he’s not Vader anymore, he’s back to being Anakin. the humanity that the emperor hid behind the mask has been revealed.
Yes, but every other character that dies and becomes a ghost, they look exactly as they did upon death. There’s no reason that ghost Anakin wouldn’t have scars, missing limbs, or even be out of his armor, aside from convenience.
One could as easily say that every character who becomes a Jedi Force Ghost is wearing Jedi robes.
There are many interpretations of how Force Ghosts work, but one I quite like is that a Force Ghost appears as the viewer wishes them to appear. Because Luke believed that his father was a Jedi and a good man, his Force Ghost appears without any of Vader’s scars or armor. He is redeemed in Luke’s eyes, with the old and kindly visage that he saw beneath the mask. Of course, Luke is generally seen as a stand-in for the audience, so for an audience who knows Anakin from the prequels, they may expect Hayden in those robes. And so he appears, in some versions of the film.
I personally prefer the Shaw version of the ghost because I think that’s what Luke would wish to see, but I can’t deny others their (wrong) opinions.