I like your ideas. Only I don't feel like ROTJ should be the darkest of all the movie at all cost. Well, there must be a point, near the end, where all things turns bad - and it is more or less the case in the actual movie (rebels capture on Endor, space battle avorted, Luke in trouble) - but I don't see anything wrong about a real happy ending for the whole saga. We already have three movies with a kind of dark ending (AOTC, ROTS, ESB). I personaly would let the other three with a happy ending. It would bring balance to the... oh well, you got me! ;)

But this is YOUR fanedit, and this is just my opinion. I like to watch new visions of this movies anyway. best luck with it!