My guess on the red light...
I guess it indicates that the batteries on the wireless controller are about to fail on you, since the rumble should chew them up. I bet several people will claim for a über-capacity battery pack for these, or a wired version.
On other point of view, only REAL joysticks (First generation Microsoft Sidewinder, a couple from Logitech, and few from Thrustmaster, for example), could be called Force Feedback, since they responded with vectorial force according to the game, not just rumbling. (I'm glad they used the 'rumble' term correctly, not Force Feedback). Real vectorial response on one of these, I find hard to believe, you need some mass to be moved by electromagnetic coils, like a pinball machine's flippers, or electric motors. Pads can't have actual, vectorial Force Feedback, because they need two mechanically articulated surfaces, where to apply those said forces. Joysticks have their force applied between stick and base, if you hold only one of those, without a surface for reaction, there won't be feedback, except for a light, instantaneous inertia effect. Pads don't have articulations or anything like it, all they can do is rumble.
Now that the obvious has been set aside, rumble pads are neither new, nor innovative. The M$ joystick (and steering wheel now) with REAL Force Feedback has been around for 10 years or more.
When I bought a PSOne (a cost-down remodeling of the original PSX) it came with a single white rumble-pad. So what is the news after all? It is the same thing as saying that the latest (pick a car model) came with cup holders on the center dash on all versions.