I bought the game on PC originally, despite having an X1 and PS4.
I get straight up -wrecked- by kb/m users when playing on PC with my Xbox Elite Controller. It's so bad that I ended up just getting the game on Xbox One so that I wasn't immediately mid-air sniped from across the map by half-decent players. I mean, it simply isn't enjoyable on PC with a controller.
The REAL, previously documented issue with aim-assist is that some PC users plug in a XIM4, so the game things it's a controller and activates aim-assist, then hook their kb/m up to the XIM4 - enjoying both aim-assist AND high precision controls.