This gets into arguements about the nature of art, and at what point a creator should lose the rights to his own creation, if ever.
For the most part this has been straightforward, an artist creates a physical object like a statue, he loses the right to modify that statue once he sells it. He can't for example walk into the town square and decide as the original creator to add thirteen penises to the exterior when he no longer owns it.
Even when it's come to intellectual properties, the rights of an original creator to control their work have been very limited. A playwright might create and sell a play, but up until recently he couldn't really enter a theater and influance how someone else was going to perform the work, and say demand a given director do things due to changes he decides afterwards he wants to make, or to demand that everything about a play follow very specific requirements. Things like this had been tried for hundreds of years, and have generally failed until fairly recently.
In the case of an ongoing intellectual property like Star Wars it has come into being at a time where we have a lot of communications technology and an established enough legal system for the original creator to demand, and enforce, management rights over the idea, including forcing retroactive changes, comissioning creators to produce canon work, and then later cutting those creators out of the canon, and so on.
As a work Star Wars has gotten big enough, and influances enough people who are invested in it (either materially, or simply emotionally) that I think it needs to be handled with kid gloves, especially seeing as it could form a lasting monument that could endure as long as any statue or painting...
In looking at George Lucas' antics I mostly look towards how he has sold the rights to make official sequels multiple times, and then proceeded to invoke his rights as creator to invalidate those works retroactively, creating tons of havoc within the work itself, and quite possibly inflicting material damage through merchandise and to the professional credability of creators, as the value of non-canon material oftentimes depreciates (and being kicked from the canon can reflect negatively on a creator).
I would point towards how George Lucas once sold the rights to create a sequel in the form of a series of young adult novels. "Prophets Of The Dark Side", "The Glove Of Darth Vader", and other books were part of this series. These books were then declared non-canon through the writings of guys like Timothy Zahn. This is to say nothing of numerous other people working in the so-called "Expanded Universe" who had their own works effectively castrated
by George Lucas' own work on the Star Wars prequels.
Truthfully, it's hard to say what should be done with Star Wars, as I think it's a fairly unique phenomena, however I think it's too much to remain in the hands of one man. George Lucas might have been the creator, but left to his devices I think we're liable to see Star Wars destroyed (it's already happening) rather than becoming the enduring momument it has the potential to be.
Really, I think there is no analogy for this situation, I think something unique should probably be done with Star Wars, and that should form the foundation for similar situations that might arise in the future.
I'm tired, and I get a bit crazy when I'm fatigued, but I'm thinking maybe something along the lines of the United States Goverment becoming the official owner and manager of certain properties like this, giving a percentage of generated profits to the original creators (as the original creators) until their death, establishing canon, and carefully operating to maintain it and expand the work. The profits to be made from the IP covering the expense of managing it, with the excess going into the national debt or whatever.
Truthfully goverment appointed committees don't strike me as being good for anything, but when I consider that a step up from George Lucas managing this, that should say something.
In the end there is a point where a work grows beyond a single man, sometimes within his lifetime. Left to his devices George Lucas is liable to make this into a bigger and bigger mess.
