There are certain things that just don't fit, and a camera like the one from *Gears of War* is definitely one of them – the class isn't right, the game isn't right, and the overall world design isn't suited for a positional shooter. The feeling of presence in *S.T.A.L.K.E.R.* is very important. And shooting from behind cover is a feature in all shooters – Q and E.;)
By the way, what *S.T.A.L.K.E.R.* really lacks is the vastness of *Xeen*... or at least the fourth part of it.