Dead or Alive Xtreme. I wouldn't mind a port of DOAXBV with added minigames, but an entirely new game would be nice too. Imagine all the great things you could do:
-Use remote to aim and squirt lotion on your partner. Then use motion control on remote and nunchuk to massage/spread it around.
-Be able to play volleyball with motions - lob/pass/spike for real!
-Marine race with tilt control!
-Tug of war by actually tugging on the remote!
-Strawberry feeding minigame: pick up a strawberry by pointing at it and pressing A and B together. Feed it to your partner, by gently pushing forwards. Don't do it too harshly or she'll get mad!
-etc, etc, etc
Itagaki needs to get on this ASAP.