In my view, #; would be handy: #+(or) trips me up visually and is an idiom. I would rather remember that #; is a nulled/commented out form (like ; is for lines), and reserve #+(or) for connoting other things.
I would not be horrified if it did not get implemented, but I think I would be prone to use it.
I don't remember seeing a reference implementation link. I would like to experiment with using one if it exists.
Regards, Paul Nathan