How about Leia's real mother did not originally die and was in hiding.
This is what i put together reading the very small reference in the jedi novelization.
The original idea was probably she was one of the early leaders of the rebellion, was in hiding until palpatine found her when she went to visit her baby on alderaan at the organas and was arrested tried for treason and executed.
The drama would have been very strong here because she would expect anakin/vader to protect her from palpatine but he stands back and does nothing when she is put to death. Perhaps she was tortured to find the skywalker heir, or obi wan's hiding place?
These are far better story points than "she died of a broken heart". Like Luke says in that g4 parody "that is retarded" and i have to agree.
The sifo-dyas thing is easily explained in the episode II shooting script it was sido-dyas aka sidious. Lucas thought it would be too obvious and give away the fact that palpatine the senator was actually a sith lord, as if we did'nt already know that from the original trilogy and episode 1, LOL.
This is not the first time the canon of the oot has been changed. Up until the release of episode II obi wan was owen lars brother. Read the return of the jedi novelization, it was in the script at one point as well and talked about by kasden and lucas during story conferences. Whether or not this scene was actually filmed?
I think the dialogue was changed before they had guiness read his lines since it gave away too much if lucas wanted to make those prequels.
Up until the prequels the G-canon or george lucas canon was, the movies, the novelizations and the radio dramas. At that point in time remember their were only 2 radio plays jedi was done in 95, or 96? and did not feature mark hamill. Also i don't find that play authentic to the canon since they added mara jade as a character as a dancer in jabba's palace arica.
That kind of puts it in the realm of an EU piece.