The Dept of what you can do with it. Yes I get it, it is an tablet so you can combine television with tablet.
Well... such a combination may be the intention but it's not quite the result.
A tablet is more than just "a touchscreen".
Tablets have existed since the early 90's but no one cared about them for their bulk, weight, and poor battery life. People only care about tablets today for how the attributes they have today. Attributes that don't apply to the WiiU.
+People go crazy about the compactness and lightweight iPad and other tablets
-yet for a 7inch screen the WiiU controller is very bulky and quite a bit heavier. In fact very heavy for what's supposed to be hand held for extended periods.
+They marvel at the long battery life and portability of tablets
-yet WiiU is bound within the range of the WiiU console and has very poor battery life for a tablet and especially for a console controller.
+Tablet has had major appeal with a huge market of cheap-to-free apps from such a wide variety of developers.
-WiiU has essentially the same software model as all prior consoles, $60 per games and sparse developer support.
+Apple set the standard with
capacitive touchscreen with multi touch using pinch to zoom, rotate, and precision even with a fingertip
-WiiU has a cheap
resistive touchscreen which cannot handle multi-touch and needs a stylus for precision
And not forgetting how tablets existed in the niche of portability while WiiU controller is of course wireless but you can't exactly take it on the road.
To do more with it game developers need to do more with it. Just like as with the second screen on the DS some games make genius use from it others..others use it as Menu/Inventory area.
Well DS didn't try to be "oh, were a handheld console, and.." it was just a DS, it was it's own thing. It had a touchscreen, not a design concept of a whole separate device bolted on.
I can see the market for DS and subsequent 3DS, they are cheap and low risk for parents to get their kids. Not like a smartphone which has a bit too much adult stuff or worry about communication.
But WiiU cannot be targeted as much for kids. For one I doubt a smaller kid could even USE the huge WiiU controller with any utility and the living room space tends to be dominated by the more grown ups, Wii-1 had obvious family friendly entertainment appeal that WiiU's singular touchscreen controller seems contradictory with.
There is also a confused message, is this WiiU for someone who may be banished by low household status from using the TV so they can just use the controller screen and console? Or is it something where games NEED both screens. DS never had the problem where the top screen might not be used at any time.
And of course, how many actually care about a second touchcreen when the huge HD screen is hardly lacking in ability to transfer information. And is a touchcreen actually greater facility for things like inventory selection? Many games (like Arkham Asylum) have shown how useful the D-pad is for such things, for one you don't have to look at a D-pad, you can feel if you are pushing the right parts unlike a touchcreen where any section feels identical to any other. That's more efficient use of your different senses rather than overloading just visual.
Twin thumbsticks and shoulder buttons are a pretty damn good way of interacting with a game, augmented with D-pad and face buttons. A touchscreen in the middle is less of an addition to that and more of a side-show where you have to move hand position and where you are looking to use properly.
Live inventory screens have been mentioned but you don't need a separate screen for that, just off the top of my head, Minecraft.
http://2.bp.blogspot.com/-7aAmL1_MGWE/UKU_e1g7c_I/AAAAAAAAAKQ/Gv8L7Apn7Us/s1600/inventory.jpg
