scampywiak: I can't imagine playing Shadow Warrior reboot, Hard Reset, Doom, Quake, etc with a controller when I can do everything better with M&K. As for lack of buttons on controllers, of course that's an issue. I can map every single weapon in Shadow Warrior to a hotkey. For a game so fast paced, that's a huge advantage. Not to mention the faster camera control with a mouse.
Oh yes, the amazing argument of 'Everything you can do I can do better!' My favourite responce? I would not be able to play new Shadow Warrior cuddled to my wife on couch with M+K. Being physically free and close to my loved one in the sparse free time we have > better aiming and faster switching of weapons. Not to mention that as long as you enjoy a game, there's absolutely no point in the latter in a singleplayer game. All it does is make the game more difficult - I'm fine with that.
Oh, and yes - switching weapons is the only thing you need more buttons for. Which can, of course, be handled via weapon wheel or a similar concept with a controller. Not as efficient as numbers? True, but my above argument applies.
Well, there are more reasons than that. If an FPS is designed around a controller, you will probably have no trouble playing it on a controller. And controller is just ergonomically designed to play videogames, as opposed to efficient writing.
cmdr_flashheart: There's no denying that gamepads are less accurate/
responsive than M+KB, so I think Devs who make simplistic FPS for consoles do it for people who play those games without any desire to compete with others, i.e. people who play for leisure, or those who simply want to compete on a simpler level; some people can play really well with gamepads, but of course not on the same level as M+KB.
Controllers are generally more responsive than keyboards. The lag between a button press and an action always feels much more apparent on a keyboard than on a controller, thus far greater accuracy for platforming when using controllers.
(I believe that doesn't apply to more expensive gaming keyboards, but ... I don't care, I have a controller :D)