That's not why we recoil from it like a vampire to sunlight. It's that math is bad.
Good news! Now no one has a reason to move at all! Just like in real immersive and exciting combat.
I have a masters degree in engineering, I am not afraid of math and I see players moving all the time in combat and in more meaningful ways when we play without flanking.
Also from a mechanics point of view flanking would be an issue with the new reliance on masteries. The masteries were intended to make martials more effective and "fun" in combat and flanking nerfs or significantly weakens several of them. In that respect flanking with the new rules will bias the game away from non-casters even more than it currently is.