I think I understand the emphasis on Nintendoland, really. They seriously do not want the existing Wii ownerbase to feel as if they're being left behind, want Wii U to feel like a direct in-line update to Wii. Hence the focus on being able to seamlessly use Wii devices and an update to Wii Fit.
And that is actually necessary. A lot of the complainers seem to have gone into this with the expectation Wii U was supposed to be Gamecube 2, or something focused entirely on the 'hardcore'. Nintendo has been saying all along Wii U would play to both audiences.
Nintendoland is probably being conceived, by Nintendo themselves, as an introduction for current Wii owners to sell them on the system on the average person. Get them on board with using the padlet, combining their existing Wii accessories with the system, etc etc.
The problem is that Nintendoland isn't a Wii Sports. While a lot of people hate on Wii Sports, that franchise is actually as superb bridge game (especially Resort). Casual and experienced gamers get something out of it, and can enjoy playing together.
So they really do appear to be dropping the ball in that regard, but then, this has sadly been a running theme with Nintendo ever since Wii Sports Resort shipped. After that game, they have floundered around without crafting a really rich experience for the expanded audience that also let core gamers enjoy it. They've unfortunately fallen back on actual party games (not what cynical core gamers label party games, which can be damned near anything).
In spite of all this, it's not really the disaster a lot of people are making it out to be. Such drama! It was just a mediocre showing.
Aside from Nintendoland, I only think they made two truly big mistakes though.
1. Putting so much emphasis on Arkham City because that's a game most hardcore have already played and shelved, plus the Wii U specific features are mostly, well, lame. The kind of cheap gimmicks you'd expect lazy 3rd parties to come up with when porting games and being asked to use 'special' hardware. The game to show would have been Colonial Marines with the padlet acting as hand scanner and motion sensor. That would have blown people away.
2. Not ending with a teaser trailer for 'one more thing', probably Retro's super secret evidently GDLK game.