I honestly don't know how anyone confused it with the Wii even at E3 2011, I knew it was their next system this whole time but then again I was following all the rumors. I won't go on to call anyone dumb or an idiot neither, though Nintendo better market this thing good, I had to explain to my own cousin who is more than a casual gamer (Mainly an Xbox 360 gamer though) that the Wii U isn't an attachment for the Wii.

Because of this

doesn't seem like it would be hard to assume this was another add-on.

Ehh.. but common sense would say otherwise, again I'm not calling anyone dumb, but anyone who knows about the current state of the game industry knows Wii is on it's last legs and declining in sales sharply.

But most people don't know that this is the end of a generation. Most probably see the Gamepad like kinect was for the 360. It was a whole new thing that showed a different way to play as well as bringing a whole new catalog of games in tow, but its still the same system.

Consoles aren't known for having yearly cycles like other consumer electronics but this generation has been good with add-ons to extennd the system instead.

You and I may know that this is a new product but for others this probably looks like the Udraw pad.

Part of the confusion is Nintendo's fault. Of course gamers know that Wii U is the new console but casual players/costumers are not really sure what that U means. For an American standards the "U" indicates that is an updated version of the Wii. Usually when in the Western market you add a letter or symbol to the title of a product indicates that is an update not a new product; like using "+". Also the pictures going around when the Wii U is using Wii Remote and the fact that the design of the Wii U looks so similar to the Wii confuses even more the average customer. If Nintendo wanted to avoid this problem in the Western market they should gave the console a new name or at least called Wii 2.
Reporters are also to blame, they really should be well informed before writing an article. Big news sites like CNN already published articles of "How the Wii U works with the Wii".