I doubt it will be possible on a console and it sucks. But I believe the one to blame is indeed Microsoft and their XBox.
Thinking about it, Project CARS on XBox allows you to map everything you can just like on a PC, of course a controller or wheel only has so many buttons. When I fire up the game next time I'll see if it's possible to map all buttons to separate functions. if so then it's not the XBox One to blame.
@sofa: XBO 1TB + Elite Controller ~ Samsung 65" SUHD curved 3D LED TV ~ 5.1 surround home theatre
@rig: XBO 1TB ~ obutto r3volution ~ Thrustmaster TX + T3PA + TH8A + Leather 28 GT ~ Samsung 50" 3D Plasma TV ~ H&K Soundsticks III