I'm curious, but why this kind of flag-standardisation? In the real world, flags are of myriad shape and size.
Don't take me wrong, I agree with your other points (those are basically the guidelines for all heraldry - it should be simple, and easily recognisable), but the regulation of size is just weird. Why should a nation have a flag in the first place? You could have banners, like the Romans. Or you could have a Japanese-style high-flag.
EDIT:
On a side-note,
probably the best vexicological site in the world.