Something about it still didn't quite hit home all the way, though, and it feels like that was the part that will allow for the Mii integration. The level design made up for the art design. I strongly disliked NSMB DS, but I had a good time with the Wii iteration. Yeah, I wish they'd do more stylistically, but I don't mind too much as long as the levels are well-crafted. From a practical standpoint, the NSMB series proved to Nintendo that they don't have to make drastic changes to and it's still guaranteed to fly off the shelves. Though I do hope we see some more interesting use of the Wii U functionality, it's hard to say what they'll do with this game since the demo's only official purpose was to show the game cloned onto the remote screen. Yes, they could improve the graphics some, but I'm not expecting significant changes.
Much like when NSMBW and SM3DL were shown at E3, I expect some of the levels we saw will make it into the final version. It was already running at native HD resolution with higher-res models and completely new levels. Last year's demo wasn't just NSMBW upscaled.