So I'm guessing that the 3x people posting here that played the first game with KB+M didn't spend any time aiming or shooting...?
The game STILL has a disastrous amount of positive AND negative acceleration. It's baked into the engine. You can't mod it out, and at no point since the game's release 2.5 years ago have they decided it's worth fixing.
Moving your mouse 1 physical inch can be either moving your crosshairs 10 degrees, or 180 degrees depending on how fast you do it. it's BY FAR the WORST KB+M implementation in a PC game in over a decade.
For a game with very promising multiplayer, it was disappointing. very.
The sequel doesn't suffer from this, for that alone it's leagues ahead of the game to where the last one left off.