Picked up the Halo Reach remaster that launched on PC today. Jump into multiplayer, get destroyed non stop by headshot and my mouse had crazy input lag.
Google to find out that people who play with controller get aim assist. A bunch of streamers and pro players are saying controllers are insanely OP and it was true about mouses having bad input lag. Some pro players got used to the input lag though and managed to get good with the mouse after a ton of games because they figured out how to adjust. Some had to cap their frame rate to fix their input lag.
I plugged in a controller myself to test it and the shit is retarded as fuck. Your crosshairs stay stuck on people like glue with the aim assist on. I don't remember aim assist being this bad in old Halo games on Xbox and Xbox 360, although I never played Reach, quit after Halo 3, so maybe Reach was this bad on 360.
They should have different matchmaking for controller players and keyboard/mouse players.