Come to think of it, I wonder what all the applications for HD rumble are in Nintendo games? It probably won't get much use year 1 aside from experimental titles, but aside from that. . .
The first thing I thought of was the sensation of Kirby sucking something in. That'd probably be a project started late enough to work directly with the system since they were busy just last year. There could also be individual rumbles for various powers or being hit by various attacks, too. If they implemented it, the bosses would probably have a couple of additional rumble types as well.
Anyone got a Nintendo title they can picture with significant use of the function?