There are several problems with camera shake.
1) As we know by now, some people get nauseous from it. I never had this kind of problems neither in real life situations nor in any games I played, however, after playing a full match as a berserker in KF2, I get a headache. I suspect it may have something to do with putting additional strain on muscles that control micro eye movements, as they work overtime to stabilize the vision during KF2 match.
2) It breaks immersion for me. When the character I control moves on his own, that reduces the feeling that I'm in charge. Instead, it feels like I'm just along for a ride in some autonomous body.
3) Generally, the amount of swaying and shaking in this game is greatly exaggerated, especially during reloads. Putting in a mag feels like getting bumped on the street by some rude bulky guy. Same thing with feedback from using a melee weapon. In real life you can hit a concrete wall with baseball bat all day long and you won't notice that much shaking, as your arms and body frame will absorb most of the shock, while neck and ocular muscles are doing a great job in stabilizing your view.
4) In most of games, camera shake is a form of punishment for player's mistakes, like going off track in a driving game, etc. It makes it harder to control your character, and it's something you instinctively try to avoid. I would surely understand some camera shake as a result of taking damage, but in KF2 it feels like we're being punished all the time, for no apparent reason. Especially when using melee weapon, where every swing at a zed feels like a punishment, and the whole game as a chore rather than pleasure.
The best way to go about it would be an introduction of a global camera shake off switch in game options, so both people like me and those who like this constant Parkinson's fiesta could enjoy the game.