Something that I believe is driving many changes is the evolution of the prequel storyline.

It vaguely focused on Ben's story when the the OT was made, but as the PT was developed, Anakin became more and more the main character til eventually the six-film saga became "The Tragedy of Darth Vader." The addition of Hayden and the "NOOO"s to Jedi are, I think, efforts to emphasize Anakin's place as the (now) main character. A more fatherly Anakin ghost makes sense for Luke's journey, but now it's all about Anakin. Adding a line that reminds us of ROTS obviously makes us conflate ROTS Anakin with ROTJ Vader.

There are remnants of the original thoughts in the films. "When I left you, I was but a learner," Ben calling Vader "Darth," Vader not being a real viewpoint character in ANH... etc.