how does a keyboard & mouse give an unfair advantage? Just force a medium-low sensitivity on the mouse and you should be equal

Mouse and Keyboard have an advantage over GamePad because the Mouse allows for quicker reflexes and increased accuracy - you are using an entire hand to aim, compared to a thumb for a gamepad. Because you can aim with your hand on a mouse, you can have the sensitivity higher yet still have more accuracy than a gamepad.

Microsoft tried pitting the best Xbox360 players against average PC players on a multiplatform demo to see how it would work out, and the Xbox360 players got annihilated. Because of that, Microsoft ditched the idea of a multiplatform release.

But this game doesn't rely on accuracy, Its a bunch of fantasy races running around and cutting each other to pieces so I think it would be a cool thing to consider and test for this game but probablywouldn't work for a shooter.