I'm looking for motivation to go ahead with P3DV5. Can you tell me why you believe DX12 has made P3D a winner.
One word: performance.
In my setup of a real 737 cockpit and three 100" projectors/screens for 210 degree view using 3 P3D windows it makes all the difference in the world. I am now able to set nearly all sliders to max with nVidia Control Panel VSYNC ON and Half Refresh rate which gives my an absolutely butter smooth 30 FPS! There are only a couple airports where it drops to 26-28 FPS.
I use Sim-Avionics 737-MAX suite and their flight model, so no frame killing PMDG or anything. I also use AIG AI at 85%.
Hope this helps.
nVidia Titan Pascal