PT Did Lucas go too far in Revenge of the Sith?

According to the Making of ROTJ HK was referencing the ghost idea that he had heard from Lucas himself earlier.

Lucas was not committed to it from the get go but thought about it. So both the ghost idea and in fact the funeral pyre scene were added.

Of course he also had Obi-Wan become corporeal again and Yoda deflecting Sith lightning as well so it was fluid.

Actually apparently the entire funeral pyre scene was done because someone asked "What happened to Vader's body?"