I'm thinking that the part of the controller used for aiming (in a FPS; probably left), would be used much like a mouse would. But, on a vertical plane (in the air) with no depth, instead of a horizontal plane which the mouse uses (like a mousepad). So anyways, there's this imaginary square in the air that is a vertical plane and your hand is right in the middle of it; you move your hand accordingly to what you would like to see on screen (thus using the camera yourself). Like If you want to look up, you move your fist upwards, not above your head. Once you go out of this imaginary square (how big the square depends on sensitivity), the camera moves faster in the direction you wanted. So if you move your hand out of the square to the left, you spin left faster. The farther out, the faster you spin. This allows you to always view the television; so if you want to turn around in the game, you don't have to turn around in real-life. It would be best to ignore tilt and rotation on this part of the controller, it would allow for greater ease of use. I guess you could use the gyration based solely on tilt (as if your holding a big analog stick), but I think that it wouldn't be as fun. The other part (used for shooting and such) tilt is a definite must, becuase aiming is almost always based on how you tilt your hand/arm. Also rotation should come into play, turning your hand sideways results in turning your gun sideways on screen. The gun part of the controller should be able to sense everything really.
If your not getting my explanation on how you view; pick up your mouse pad so it's vertical and then use your mouse. While a little ackward, moving across the screen is still how it use to be when you had it on the desk. So, you should see that it still works (unless you have a mouse with a ball instead of a light), but ya you get the idea.
A flight stick would just sense tilt...no need for rotation or even up and down as well as side to side movements.