I talked a bit about that myth on the other thread, archer 2. How can a difference of only 12/10,000ths of a second that a fast arrow is on the string vs a slower one impart any real increase in 'forgiveness' to a reflexed bow? That's comparing arrows on a bow with 7" brace and 30" draw, 250 fps arrow vs one at 300fps. I simply don't see it happening. The shooter would have to be torquing the grip from the get go for it to have any impact at all and he's still going to miss anyway. If that were the case, he'd be better off with the deflexed riser because it would be very difficult to torque to begin with.
Bows still have reflexed geometry simply for the sake of speed. Even with all the 'advances' you talk about, that's still the primary reason. Yes, with parallel limb technology, they have to use reflex risers to keep from having very high brace heights (and very slow arrow speed!). Sure, they can build a lot of weight forward mass into their reflex bows and put on teensie tiny grips, then the shooters add massive stabilizers, all for trying to make them a little harder to torque, but they're still torque-y sonuvaguns compared to a deflex riser.
You know, my back messed up on me really bad 15 years ago. I've lived with varying degrees of pain ever since. I don't remember what it was like to wake up in the morning without hurting. So many people have shot reflex riser bows for so long - and many have never shot anything but that kind of riser - that they don't remember or just flat don't know how steady a deflex riser bow holds on target, how much more leeway they have in how their hand is placed on the grip, or how consistent their shooting can be with one. Kinda like me with my back. It's hard to tell the difference between deflex and reflex riser bows when you haven't shot deflex in a long time.