Fixing the mail system would probably take an entire recode if we were to do it, and possibly recoding other parts of the client/server entirely, too, to make sure it didn't contain exploits of any kind.
So, I don't think we'd be doing that. It would be a massive project.
Actually i would love a system like that, i had to wait half an hour till someone i knew got on so i could transfer a handful of items, which is really annoying.