After reading this I'm actually kinda glad I don't own Rock Band yet, now I can get RB2 with the improved instruments, and buy a stand alone copy of Rock Band for cheap.

Personally, I think rumble can be an integral addition to gameplay, particularly with FPS, action, driving and flying games. For example in Gran Turismo 4, I use the rumble all the time as means of sensing what the car is doing, and if you know what to look for, and what kind of rumble to feel for, you can actually use that feedback to determine if and what tires are about to lose traction during a turn. Another example is FPS; there is a world of difference between simply pressing a button to pull a trigger, and pressing a button, feeling the trigger click, and then feeling the weapon fire.