Sorry, I mis-read that. Surround channels aren't the primary "non-Atmos" channels used for creating the object placement. It is created, at least in its current upcoming version, via the front channels and overhead speakers.
Who knows what the future will hold, but since your ears face forward, the idea is that you won't be able to detect audio points in space behind your ears, and thus the surround channels won't matter if they are direct or di/bi/quad pole.
What you are getting from AVS is people's personal preference for their existing surround speakers, regardless and outside of an Atmos implementation.
With that said, and yes I do love having four QS8 surrounds, I have always wondered about switching to direct speakers instead of the QS8s for surrounds. Not because anything is wrong with the QS8s, but I feel that from my front row of seats, the rear surrounds are "too diffused" by the time that they hit that row, and that is the row that I sit in... Yes, it is all about me.
Again, I will report back as to what I see & hear, and what I can learn from talking to the Dolby Atmos guys themselves in person in 2 weeks when I am at CEDIA.