Well, first I'd like to say to the person who started this thread: the original-trilogy forum isn't the best of places to start about changes being good. When you do that it's either to provoke or to get pooped on deliberately. But about the things you suggest to be changed, they are ridiculous. Adding CGI material to a movie from the seventies?! Come on, there's no way you will get that to fit/blend in, just put one of those official DVD's on and you'll see what I mean. All added CGI is very badly done, no realism whatsoever, it's just destracting.
You really shouldn't tamper with something that's earned such a wide appreciation, after 20 years it has grown on to people, human nature. And there is no reason to change anything in the first place: the OT has proven itself the way it is. My opinion is, if you really MUST change anything, just fix some flaws and leave it at that.