Even though Nintendo's new Wii U was playable at this year's E3, the console wasn't exactly looking its best. Control pads were tethered, and most demo units were hollow cases, the games actually being played on dev kits. There's even the possibility that the design we saw at the show won't be what the Wii U looks like when it's released.
By E3 next year, though, the console should be good to go. Nintendo president Satoru Iwata said, "We would like to show the final format of the Wii U at the E3 show next year".
"As we learned a bitter lesson with the launch of the Nintendo 3DS, we are trying to take every possible measure so that the Wii U will have a successful launch."
Interesting statement. Here's how I read it: you won't be getting the Wii U until after E3, because you won't be getting it until there's enough decent games available so people actually want to buy it. That's how you learn from a bitter lesson!
Semi-Annual Financial Results Briefing [Nintendo]