It's getting really bad with people playing mods to run a mouse on the game. It seems like every other game I run into someone that is turning faster than a 20 setting on sensitively, complete recoil management without missing a shot, and pin point accuracy without delay. You win some and lose a lot in this game, and I never assume someone is cheating. I usually spectate after I get killed and the number of people that is easy to tell they are using a mouse has greatly increased. Watch some of the top players videos on the leaders board. One has a picture of all his sensitively settings on 5, but turns faster than if you set it on 20 with a controller.
They need to do one of two things to fix this.
1. Have a reporting opinion when spectate against possible mouse users ( you can't tell unless you spectate)
2. Allow mouse and keyboard on all platforms. I don't like this option but at least everyone will have the option to play on an even field.