I guess that's the flaw of ego: We don't want people stealing your replays, or ideas, but somehow, purely rational it would be logical to allow edits. If it's better and it's on your name it should be your record. But I don't know. I think we shouldn't allow edits, the record book is for honour, and some noob getting away with your great setup after changing one joint is harsh.
I doubt it, I think the main reason people are against editing replays is because they dont want someone maybe accidently chaning their brilliant setup for a record, with one joint difference, when perhaps they wouldnt know how to do the setup otherwise. So chaning your own replay would be fine, no?