I agree with the modifications ideas for calm to moderate windy areas and I think for backpacking the shortening is a definitely a good idea. Holes also make sense, especially for alcohol stoves. You ideas would make it alot like other screens I have used, except for the hinged folding aspect. Adding another panel would be good for wider pots.
But it seems to me that the high walls work better in strong winds. Having the large opening on one side has seemed to work surprisingly well even when simmiring with a small alcohol stove. I was surprised about this, but maybe the height has something to do with it.
I have compared other shorter windscreens and have found the taller screen even with the one big opening has been more efficient in strong winds, if the opening is away from the windward side.
My tests with my high walled screen, with the big opening on the downwind(leeward) side allows the flame to stay wrapped around the whole pot and maintains the focus of the flame.
On shorter screens the wind tends to suck the flame/heat away from the pot. The wind tends to blow down the windward side and exits the top of the downwind side of the screen. You'll see the flames blowing out the downwind side with much of the heat not reaching the pot. The fact that the wind is blowing and cooling the upwind side of the pot can't help matters either.
This is even more important with alcohol and other more precious fuels. The fuel you save could outway the extra weight of the additional height.
Of course your milage would very depending on the winds you tend to encounter.
Because I travel by kayak and tend to be near open ocean, I see more winds than most backpackers, but not all.
I have found that the Kelly Kettle has been more efficient than almost anything I have tried for boiling water in a strong wind with wood fuel and I suspect the enclosed flame to be the reason.
I guess I'd have to be more scientific if I wanted to gurantee my findings though