sony said that a rumble feature in the SIXAXIS would interfere with the tilt functions. I personally dont see this as a bad thing. For example, MOTORSTORM. The vibrate function could be used to make the controller to go "out of balance" so to speak, as if the car was going over a bump and pushes the steeringof to the side, adding to the realism. and WARHAWK, vibrates when you are hit by a missile, and the plane gets shaken and slightly looses control for a second.
What are your thoughts?