My take on K/M vs Controller: Mouse is vastly superior to the analog stick, but the analog stick and buttons milimeters from your fingers is vastly superior to the keyboard. You've got more buttons yeah, but when you have to press a button with your pinky as well as the A and W buttons with your ring finger and your middle finger to move diagonally slowly, you realize that moving your thumb slightly to the top left of the analog circle is easier. The keyboard just isn't efficient.
Same with crouching, and with macro keys on the controller, even being limited to about 16 buttons isn't a real liability. Not to mention all those buttons are placed ergonomically within a very short distance from your finger.
Honestly, gamers could do a lot more with a controller than developers give them credit for. However, I will reiterate, the mouse, especially the ones with several buttons on top of the normal ones, is vastly superior. The accuracy afforded and the speed is bar none the best option for aiming in FPS. With the added buttons it becomes very similar to the ease of use of a controller with buttons within easy reach. The keyboard just isn't in the same league of efficiency as the controller.