Picture this: You are in charge of designing a new game for the Wii. A new peripheral has just been announced, EXTRA STORAGE! You have the first shot at creating a game using this extra peripheral , so...

What kind of game do you make? And what is the main gameplay mechanic behind it?

START!

(NOTE: Do not blame me for starting a rumor, this is just a hypthetical)

I would make a game where you make your own game. (kinda like that black playstation 1 where you made games) .

That would be killer

a mmo rpg....that drops friend codes in favor of dedicated servers with downloadable content that can be user created

I would create an MMORPG! YAYEE!! It would be a motion based control scheme like sword fighting and gun play. I would make it also as interactive with the environment as possible. Then I would make a game that you can mod easily and create lots of jumbo stages. Perhaps another RPG or ... an RTS.

but i would try to limit how much party dependence you have---weaker enemies when your by yourself and tougher ones when your with a group..that way you can just pick up and play with out having to team up

I'd create road rash Wii.

What does that have to do with storage? nothing. Do I care? NO!

A dungeons and dragon game that actually plays like dungeons and dragon and not Balders gate or some other crap.

With online functionality and plenty of ways to customize rules, just auto allow stuff and store games.

I mean how hard is it to make D&D games that play like D&D!

Also... Hot seat ability for campaigns that can be set up to be run by the computer. 

Something uber-casual with tons of easy-to-get-into, pick-up-and-play, hard to master and heavily addictive minigames. Set in a varied, huge, easy to navigate sandbox overworld you could walk around in with your Mii. Downloadable content, like new games every week, mii-integration, simple online play, great multi- and singleplayer modes and funny customization options. It'd sell millions.

@kas--ts only fun when you have a crazy mod that bends the rules--played a game one time where a friend pissed him off so he had a meteor fall from the sky...it was 300 feet wide that could only do damage to dwarf wariors...he was the only dwarf warrior....omg that was great

I'd create a level editor for Super Mario Bros., that lets you combine level design elements, items, and enemies from SMB1, SMB2, SMB2USA, SMB3, SML, SML2:6GC, SMW, and NSMB.

You could trade levels to friends with friend codes, and submit them to Nintendo, and the best would be shared. You could make them hours long and save them all to your hard drive. You could make a level that's miles and miles long with 30 save points, or a million short levels into an entire game.

It would be heaven. Nobody would ever make a platformer again.