Forgive me if you posted something similar, i havent read everything in the thread yet.
my game would be a free-roaming 3rd-person shooter in a sci-fi setting. Sounds generic right? Wrong. It's not your generic Halo/GoW type shooter with sbeefed up space marines. You take control of either a cyborg or automated power-suit (whichever is better for story) that can move in 3-d space. Think something akin to Iron Man.
You stand nuetral on the balance board and shift your weight left/right to strafe, put weight on your toes/heels to move forward in backward. there is no "hold this button to draw your weapon, press this to shoot" like RE4, cuz you'll need to shoot ASAP since things can come at you in all directions. You fight in space mostly but missions can take you to land areas as well where you have more of an on rail feels, since you won't need to manauver as much; these will be run-and-gun missions.
Its not all point and shoot though, boss encounters will be against massive .... things.. whether bio-weapons or mechanoids or just giant enemy cra..crafts (almost said crabs

) and there will be some puzzle elements too them and not just shooting.
You're flying thru space, take out an armada and here comes a gian battle cruiser type thing, what do you do? It has 4 giant gun/missile turretts that also act like armor protecting the inner core as well as cockpit to the enemy. You notice something... Hmm.. they must of gotten this thing out early in a desperate attempt to stop you cuz you notice some latches that look a little unfinished.. a little.. weak. Your blaster or whatever doesnt work but it looks impervious to high temperatures...hm... !!!! You got it, you figured out what you have to do...
You rotate yourself so your feet are above the hatche and you have to carefully shift your weight to steer the flaming jet propulsion system on your feet to trace the hatch and get your way inside. Theres a narrow space but you know you can get by if you steer carefully enough. You dont want to crash into the walls.. not only will it cause (minor) damage but it'll alert the enemy you're inside setting off a trap that can possibly kills you. You make your way to the control area for this one sector and nside you see a few high-tech doodads but just destroying them won't work, you need to detach this part of the ship from the main body not just disable the weapons. You do input some codes (ala Metroid Prime 3) and then use some waggle to hit the release. Vioala!
Rinse and repeat.
Your blaster wouldnt be your only weapon, you'd have some melle attacks too controlled via the nunchuck and they could be used simultaneously (sp?). I can't think of something original right now so i'll just steal something from Sin & Punishment; You'll have some sword of energy sword to atack with at close range.
Once i presented this to nintendo, they'd greenlight the idea only if i made it a StarFox game. I'd have no qualms about it, but everyone here would.
EDIT; i'd also make a racer where you use the balance board as pedals and stear with the wiimote/and or nunchuck. with so many thigns you can do using the balance board and wiimote + n-chuk.. Not only are so many control options possible but so many ideas are possible. I'll have to come up with a good one...