Seems reasonable. The key question becomes, how does human hearing perceive this case, having particle velocity and direction with a pressure null? My entirely subjective self-experiment suggests it detects a sound, the particle velocity triggers some response, not "nothing" which a pure omni detects.
I've done this. With the UMIK-1, as I move further forward into the room, the 70 Hz null shifts to a lower frequency. That's how I know it's LBIR from the rear wall. However, the NT1A mics (and my H4 recorder's built-in mics) never show this null, even when I face 1 forward and 1 right behind it facing back.
I suspect that human hearing is not completely cardiod, nor omni, but something in between. The article I posted earlier says it's cardiod-like at mid to high frequencies (with diagrams) becoming "more" omni in the low frequencies. But still not completely omni even at low frequencies, because I can hear the 70 Hz dip but it's perceptually quite small, much smaller than the UMIK-1 measures.
If true, then omni measurements are still useful for showing peaks & nulls for tuning rooms. But we need to find out where the reflections causing them are coming from. If they're coming from behind, as in my case, then do not correct it fully, but only correct it partially. Because we don't hear reflections coming from behind, the same way an omni mic does. Our head & ears attenuate it somewhat, while an omni mic doesn't attenuate it at all.