If you are going to argue that "horsepower doesn't matter" then why should anyone bother upgrading now? Why not just stick with a PS3, or 360, or one of these Android based consoles (OUYA and onward)?
The argument for the Wii U, is that gamers NEED to have a second screen in their living room. That is IT for the Wii U. So, you need to argue why this second screen is such a critical feature that it will win over hardcore gamers that you had stated it would, because the Wii U is supposed to be a "hardcore" console, according to your estimate. The Wii U is supposed to outdo a PS4 that is more powerful, with much larger internal storage, and ONLY $50 more expensive. The WiiU is supposed to do this without really an EA support and every third-party turning their nose on it, as far as next gen console content goes. The Wii U gets current gen stuff, to some extent, but is this stuff really being shown that much better than current gen stuff?
Second screen and Nintendo's exclusives are what the Wii U has. Is that enough?