Star Wars: 20 Things You Didn't Know About Return Of The Jedi
17. Obi-Wan Came Back From The Dead In An Early Draft Of The Script
Though Obi-Wan (Alec Guinness) of course appears in the film as a Force ghost, an early version of the script actually had the Jedi resurrected in full corporeal form.
Ultimately, the decision was made somewhere along the line not to do this, which despite the obvious fan-serving potential of the character's resurrection was probably for the best.
Given that Star Wars has enough problems as it is with death having any finality, bringing Obi-Wan back for sentimental reasons - rather than ones that made sense to the narrative - would've been a massively foolhardy step in a film which already had plenty of narrative plates to spin.