The funny thing is Had Abbadon was reused in the EU legacy comics series for a volcanic planet much like Mustafar. Gee the original storyboards for Return of the Jedi showed the imperial homeworld had Volcanic activity down in the lower regions of Palpatines Palace. Vader and Luke would have dueled over a pit of Lava. Lucas told Joe Johnston to stop work on it and he would save it for another day.

Still in that same draft Ben comes back bodily from the netherworld and yoda as a ghost to help Luke in his fight, very bad idea.

Lucas first ideas are not always his best. He was going to have a 13 year old Han Solo in Revenge of the Sith who with Chewie whose family adopted Han and raised them together as brothers, meet and help save yoda. He was supposed to be according to Lucas notes i think based on memory like Tom Sawyer and Tarzan.