Yes I think its a bit naff too, wouldn't quite go as far as call it a rumble, more like a mobile phone vibrate. Really noticed it on the Fifa demo when it was vibrating for a penalty shootout. On the 360 that rumble effect works there as a tension induced pounding heartbeat, but on the gamepad its just a naff loud buzz and a shake of your hands not quite the same (or desired) effect.
A small thing to mention, but what do people think of the vibration on the gamepad?
I don't like it, feels like a weak electric toothbrush is inside it when it goes off.