Nod, some of my panned shots are several images into a sequence, where the car was tracked as I moved the camera, my panning isn't great but when it worked, it worked well.
I also took a couple of sequences of cars coming offset towards me, perhaps at 30 degrees, with a high shutter speed, the camera nailed the focus every time.
Whilst I appreciate that it may not be up to DSLR standards, the X-T2 is a long way ahead of the X-T1 in this regard, and certainly usable for the type occasional tracking that I do, that GK Jnr is taking them to an F1 event also speaks volumes.
With regard to high ISO capabilities v the D750, the same pixel resolution on an PAS-C sensor will never match that of an FF sensor, the laws of physics indicate that, but on several occasions I've had ISO 12800 images from the X-T2 that are more than useable, which would never happen with previous generation Fuji's. Again in this regard the camera is a step up.
The DSLR v Mirrorless debates will rage on (I suspect for many years), and really it still depends on what you shoot the most and what sort of physical size package you require, but all I can say is that the X-T2 has moved the performance of the Fuji Mirrorless cameras on by a significant amount (just to be clear I've not used an X-Pro2), combined with some really decent glass,it is now a maturing system.