I really don't think this is direct response to Wii U tablet controller, and if it is - it's not a very good one.
Wii U tablet has buttons and screen in one device you hold in your hands - I can't imagine constantly switching between 'traditional' Xbox controller and Android/iOS/Windows 8 tablet, whereas switching from pressing buttons to using touchscreen on Wii U is infinitely easier.
Wii U tablet has buttons and screen in one device you hold in your hands - I can't imagine constantly switching between 'traditional' Xbox controller and Android/iOS/Windows 8 tablet, whereas switching from pressing buttons to using touchscreen on Wii U is infinitely easier.