The only unaltered version of Star Wars is the one that played in theaters. If we were to use DanielB's definition of what the "original" trilogy is then it would be the made only with elements created at the time or prior to its theaterical release. DanielB said that minor changes Lucas made up to 1993 didn't bother him much (i.e. could still be called original), but the only original was only seen between 1977-and 78 for a re-run. This is the only one that could and should be called "unaltered."
One thing has been made abundantly clear through all of the versions that have come out. Lucas and his crew don't have an eye for detail. If they did, the glaring errors here and there throughout the trilogy would have been corrected.
Lucas can have a few minor differences, IF he's using the original material. That I'm fine with.
MeBeJedi is catching flack over just a few frames of lightsaber cleanup. If the "method" and/or "process" that MeBeJedi is using is something that was created prior to Star Wars coming out, and it is a method that Lucas revolutionized in his movies anyway, wouldn't that be nearly the same thing as using the original "material?"
Now I've got an analogy for DanielB. When trying to preserve an old book, the people doing so have to go to some great lengths. Let's say that a page has come out of it and it is in such bad condition that it cannot be reattached to the binding. The job that they are faced with is copying the text from that page onto a new page and attaching it to the binding while keeping the look and feel of the original document. This could entail using paper stock from the region it was produced, using a array of inks that were special to the time period it was published, etc. The overall purpose though is to make the new page look and feel like the original document, while making it stronger than the original that had come out.
Now let's compare this to what MeBeJedi is doing. Several frames in the movie have noteable effects errors. He takes the effects a frame at a time, duplicates the methods (albeit an updated version of the methods) that were used to accomplish the original effects, and prserves an effect that had been looked over. The result is one that looks and feels like the original frames, but is stronger/better than the original. So in essence, when you talk about preserving film history, MeBeJedi already is.
Honestly, I see this entire debate as being rather silly. I am simply playing the devil's advocate for what can and cannot be called "original" and "unaltered."
Rock on MeBeJedi.