This would be really helpful when viewing a set together, especially in grid view or for the impromptu slideshow. Otherwise, you have to manaully drag images around until they are random. I imagine this would be a quick feature to implement.
Weird, it doesn't for me. That's a really funny and highly un-intuitive way to do it that makes no sense. View > Sort is the ony thing that affects Impromptu Slideshow for me.
My primary need for random is grid view (sure I could put together a grid on Print or Web, but that's insane when it's a simple Library viewing task). The View > Sort menu should really be the only thing affecting anything on Library including Impromptu Slideshow. I can't be the only one that needs to look at a grid of images in random order.