Crouching has nothing to do with looking down the sights of a weapon. Iron-sights are about taking a step forward in realism.
To those of us that actually do like shooting real firearms, the CS gun-handling mechanic is very fake and unrewarding in that sense.
Don't misinterpret what I'm saying here...because I'm not saying your game is "bad," but it is tiring listening to CS guys go on and on about how great CS "gunplay" is when it is in fact about as arcade as it gets.
I don't want to come off with Crysis fanboyism here, but the amount of effort and detail that CryTek put into the weapon mechanics of their game is amazing. When you aim a real rifle, and rotate your arms or body, you'll notice that the forward sight actually shifts to the inside or outside edge of the rear sight. You can actually see this intricate movement (and see it's effect on aim) when moving while sighted in Crysis. THAT is cool, and it is obvious that they had some actual firearm expert input for their mechanics development.
But I'm not saying that CS should be about that. I don't care if they change the gunplay or not, because like I stated earlier, Valve should listen to what the CS fanbase wants, and that's obviously what they want. More power to you all.
I only take issue with the condescending attitude that a lot of CS guys have with the whole "CS gunplay is perfect" thing. CS isn't the only FPS out there that requires skill.