I have a Thrustmaster T150 setup, and I agree it is frustrating not being able to remap buttons. On Need for Speed 2016 I remapped my nitrous to one of the paddles and my handbrake to my clutch (I just play NFS type games automatic instead of manual). The default handbrake setting on Payback, which I can't change, is the square button, being the furthest button in for my right thumb. How does that make sense when they could've at least mapped it to circle?
NFS 2016 also handled perfectly for me without changing my wheel setting from 900 degrees rotation. For Payback I had to lower it to the lowest setting, being 140 degrees before it felt playable.
That being said, I do like how it handles at 140 degrees and I enjoy using the wheel. I would just like to be able to remap the buttons and also have access to advanced wheel settings.