2, 3, and 6 are resolved in newer projectors. 4 and 5 are also gone with ultra short throw projectors, although they do have to sit on something. And 1 can be solved with a screen or even the right sort of paint.
I use an ambient light rejecting screen. They only reflect light that hits them from directly below, to pair with a UST projector. It's still not comparable to an active display, but it is usable during daytime, even in rooms with large windows.
