Stereo is very different than two mono channels. You should read up on stereo microphone techniques.
While the OP is wrong in his conclusions, there is some truth in his thinking. If you position your speakers as he suggest you would minimize any crosstalk cancellation between the loudspeakers. This is something that Phase Linear/Carver did with their autocorrelator and Polk with their SDA loudspeakers.
If you want to experiment with the concept all you need to do is place absorptive material midway between your speakers and extend the material to the listening position. Your listening space is effectively bisected. Ideally the only sound that reaches your right ear is coming from the right loudspeaker with the same for the left ear/loudspeaker. I listened to a demo of this approach back in the early 90s and it did create a very convincing stereo image without the headphone like hole in the middle.
And even though I disagree with the OP what he suggests cost nothing to try. I further applaud the fact that he didn't label his idea the "Quantum Speaker Placement Theory".
