Paul, you are certainly on the right track in terms of the design principles that should ultimately lead to true fidelity in a loudspeaker. Unfortunately, there are always tradeoffs in every speaker design, and every implementation of a given principle has variables that lead to differentiating sonic results. In other words, there are no perfect speakers.
I am a huge fan of time alignment and phase coherency, evidenced by the fact that for the past 27 years I've owned a pair of Beveridge Model 2 SW loudspeakers. These are full range electrostatics with no crossover ( I eliminated the high pass X-over) save for the low pass on the subwoofer. This speaker probably comes as close to a perfectly time aligned and phase correct speaker as any design ever made, but it still errs in ways important to music reproduction.
The bottom line is, whether a speaker's design is critically time aligned and phase correct or not, ultimately it gets down to how you perceive its ability to reproduce music. I have long admired Theil's work, but at Theil's RMAF demonstration this year I was most disappointed in the sound of the new 3.7s. To me, they had a coloration to their sound that was akin to holding a long piece of tin foil between two fingerand shaking it. Everyone who heard it at the same time that I did reported hearing the same coloration. However, someone from our group who heard it later didn't experience it that way, so maybe there was something else contributing to that phenomena that was later remedied.
The GMAs are very fine speakers, and the C3s, when set up properly, rival my old Beveridges (I spent quite some time auditioning them with Roy last summer at his facility in Colorado Springs). Roy is an extremely competent designer, as is Jim Theil, but between the two, Roy's would certainly get my vote. Of course, YMMV.
