I'm pretty sure that 95% of ideas or (even working prototypes) that Nintendo comes up with are rejected or are shelved until later, like in most if not all game companies. It's not a good idea to reveal a game extremely far in advance. If anything goes wrong that prevents its development, it doesn't look good for the company. Case in point, Sadness.
I personally don't understand the "pics or it didn't happen" mentality with some gamers, as if Nintendo is just so unreliable that you must have proof that a AAA game is under development. What ever happened to surprises? Wasn't that what made E3 2010 so awesome? And this whole "I have nothing to look forward to" bullshit. From what I've seen, it doesn't matter anymore if a new game becomes announced. Yeah, you'll dream about it everyday but as soon as it's released you'll drop it and look for some other game to fawn over until that one releases. If there isn't one, then you'll act like Nintendo hasn't been doing anything ever. As if the entire library of the Wii exists only in the future, not in the present.
From what it looks, it probably wasn't a good idea to release DKCR, Kirby's Epic Yarn, GoldenEye, Epic Mickey, and all the other games at the same fucking time, some of which released only mere months after they were announced. It seems to only matter if they're spaced out evenly between E3 conferences, like Kirby in October, DKCR in February, and so on. You'd rather wait an extra 3 months to play something because then "it'll look like a constant stream of games?" Or maybe "Nintendo is stifling the sales of 3rd party developers by releasing all their great products at once?" Really, what the hell do you want?
If you really think Nintendo doesn't do ****, sell your Wii and your collection of 20+ games that you were obsessed about and then only played for two weeks after purchase, or shut up and GTFO. If you're a gamer, PLAY THE DAMN GAMES. Don't bitch incessantly about the immediate future and act like Nintendo owes you because you bought and enjoyed their products.