Well, thank goodness not everyone follows your thought process, or we'd never have anything such as the Wii or Kinect, which is what I'm pretty sure Valve is talking about integrating here...the same type device for the XBox, but for the PC.
Motion sensitive controls are fine for casual gaming, but do you really think that hardcore gamers, the kind who play games like Call of Duty for hours, are really going to want to stand up and contort their body for a 3-4 hour gaming session?
I've played the Wii a few times and it gets tiring.
Even if you're only using your hand to motion with, do you have any idea how uncomfortable it is to hold your arm in the air for long periods of time with nothing to rest it on. Try holding your hand up off the desk for half an hour and then tell me that's a good method for controlling games.
For the mouse, I can already tell you that optics that track the movement of your pupil would be an upgrade to the pointer aspect of things, with different "click" inputs used by blinking, clinching the jaw, whatever....
Seriously? Grinding your teeth and having to consciously blink in a specific pattern is better than using your finger to click a button? And how would such a system work? It can't 'fire' every time you blink, or you'd be entering random clicks all the time. If it requires two or three blinks in a row, you wouldn't be able to fire quickly. And what about rapid fire? Would gamers actually be expected to engage in a virtual firefight while basically creating their own strobe effect through rapid blinking? Maybe they just keep their eyes shut to fire continuously?
If using the jaw method, that precludes any kind of eating or even chewing gum while playing, since doing so would trigger unwanted clicks. It would also result in a sore jaw.
Plus, even if you still click a button and the system just tracks your eye movements, it would still be awkward. How often do you move the pointer onto a button and then take one last look at the screen before clicking OK to make sure you haven't forgotten anything. Oops, took the focus off the button. In a game, you could be aiming at one enemy when something the background catches your eye. You glance at whatever it is, which takes the aim off the current enemy, and you end up getting hit.
Text entry...obviously verbal would be the easiest method.
Even if voice recognition were perfect, which it isn't (far from it), do you really want everyone within earshot to hear your passwords? Unless we're talking about Star Trek levels of voice recognition, it still takes significantly longer to input text by speaking than it does to use a keyboard. At least it does for people who are comfortable with a keyboard. Of course, the kinds of people who aren't comfortable with keyboards are also the kinds of people who aren't familiar with the limits of voice recognition and expect it to understand full English sentences using slang.
Movement issues (WASD, D-Pad) would likely be done by either wii/kinect technology, or smaller scanners that can track movement of some sort. (Move your hand forward to go forward, back for back, etc)
For a typical game, you'd still need some kind of additional input to handle the 10+ buttons that all games today use. One button to draw a weapon, one button to switch weapons, one button to go into aiming mode, one button to fire, one button to access the inventory, one button to make selections in the inventory, one button to operate machines, etc.
And if you're going to argue that such functions should be handled by voice commands, please watch this video, specifically the part at 6:43;
Innovation is a beautiful thing, just because you can't see it, doesn't mean a better option isn't possible.
All of these options have been tried in the past and been found to be lacking in either ease of use or practicality.
VR helmets that track your head movements would seem like a perfect idea for FPS games, right? Not really. If the unit is self-contained then you have the weight of the batteries to contend with and they can die in the middle of a gaming session. If it gets its power from an external source, then you have a cord attached and can't turn in a complete circle. So it can only track your head movements so far and then has to go into 'turning mode'. like using a joystick. Then there's the issue of eye-strain and what to do if one of the LCD screens in the helmet dies on you.
Light guns are a natural for FPS games, right? Well, aside from the fact that traditional light guns no longer work with LCD screens, there's the issue of the gamer holding a pistol while their onscreen character is using a rifle or vice-versa.
Don't get me wrong, outside of FPS games and a select few others, I'm not a fan of using the keyboard as a game controller. I just don't think that all these other 'innovations' are all that practical to replace it with.
I grew up with systems like the Atari and C64 and I'm still not convinced that a little, left-handed, plus-shaped pad is a practical replacement for a right-handed joystick (for right-handed players of course).