Let me be the first to say that this thread looks like it needs sprucing up. Some antagonism would actually be nice for a change. Barring that, an injection of fresh news or rumors could help move things along.
Here are some gameplay innovations
to toss out there.
When two pads are actually playable at the same time down the road, would it not be cool to have 2-4 players traveling in a party and equipping stuff on their own screens? Players 3 and 4 could use maybe use 3DS and play along. I think this would not be too taxing, to just have menus going on at the same time. The main game could be on the tv. While in battle you could have players drawing spells on all of the different touch screens, or rummaging through their inventory to find the right item.
I think that games could be retrofitted to enable this too. Think about all of the times you were sitting there watching somebody play FF for NES or somebody was watching you play. Now, especially with games that are not graphically intensive, you could theoretically both join in on old games like that. What about games like Gauntlet that could use this feature?
How about an updated Shadowgate, Uninvited or Deja Vu? One player could be moving the character through the rooms on the big screen while the other player (an assistant perhaps?) mixes potions, tries out spells by drawing runes, or burns objects with torches. Maybe they are in seperate parts of the mansion or the city or whatever, and they have to do different things to proceed on their adventure together.
Achievements/Brag system
Think about all of the myriad accomplishments on Nintendo games that only you know about. Did you ever:
Beat Zelda or Metroid for NES in under 2 hours and get everything?
Beat either of them without dying once?
TKO Mike Tyson or Kid Dream on Punchout!?
Beat that one asshole at the end of Strider for NES?
Smack the snot out of Dr. Wiley's pet on Megaman without pausing the game?
Beat Solomon's Key without continuing?
Beat Gyruss by Konami on NES without continuing?
My point is, that these are real achievements that are probably burned into your memories but nobody else knows about them. They are probably a hell of a lot more significant and noteworthy accomplishments than say... getting 10/10 achievement points just for getting fifty melee kills in whatever FPS shooter of the month people are playing right now.
What If you re-did all of your accomplishments from older games and got reedemable points for them to put towards the purchase of whatever Nintendo merchandise you wanted? I think it would it would drives sales of e-shop games and drive awareness of all Nintendo products on a macro level also.
Just something to chew on.