I understand where you are comming from. But I disagree. I have descended my phantom 4 straight down in calm weather and it got into the Vortex Ring State and crashed, hard, from 120m. Yes that time I was in sport mode, but it is still a very real problem with the P4.VRS or Vortex Ring State was an issue for the original Phantoms and the P2 series.
DJI slowed the descent rate twice to reduce it.
With the P3 and P4 series VRS was eliminated by angling the motors which were vertical on earlier models.
It is completely safe to descend vertically in still air with a P3 or P4 Phantom.
A couple of days ago I was flying in calm weather, there was some fog around and I was trying to take photos of it but I had to keep watching the drone because it kept getting into the early stages of the Vortex Ring State. Even when it was staying still. And if I had left it, I don't think I would still have my drone