Nick the problem I see with your scenario is that a speaker is more like a flashlight. And given the speed of sound vs the size of the room along with both early and late reflections your theory may have some holes in it. Our ear/brain is quite good and gathering what it needs and rejecting what is not needed. On a strictly theoretical level what you posit would make sense but if you are sitting on the right side of the room when the right speaker produces a sound you are unlikely to hear the direct sound and more like to receive a reflected sound especially with higher frequencies.
This is just how I see it and maybe I am out in left field
I doubt I will ever be able to test this theory but maybe one day when your up and running you can give us some real world feedback. I do get what your saying though, probably will not work as well as direct as per dolby recommendations.