If the console was actually more powerful than the current HD consoles, then Nintendo would not wait this long to admit it. They would instantly jump on the Yeah were the true next gen console ship. Since they haven't, its easy to assume that its just around the same stuff as the current HD consoles
I don't agree with this thinking ...
There is a certain level of processing power (relative to the time the system was released) that represents what I would call "traditional console hardware". In the past generation, Nintendo released a system which was less powerful than this (for a variety of reasons) and Sony and Microsoft released hardware which was more powerful than this (for a variety of reasons). From the little we know about the Wii U I believe that Nintendo is returning to producing a system that is in line with most systems that have been released.
Now, why wouldn't Nintendo brag about this? The answer is simple, they can't be certain what strategy Sony/Microsoft are going to follow in the next generation. If Nintendo makes "increased processing power" a major feature of the Wii U and Sony/Microsoft release a system a year later that is $100 more expensive while they lose $100+ per console this feature can easily be eclipsed. While a heavily modified R700 that is based off of the chipset in the Radeon HD4850 can easily surpass everything on the HD consoles, and could even support multiplatform development with a console based on a Radeon HD 7850, it is unlikely going to look that impressive in terms of pure processing power against that Radeon HD 7850.
In contrast if they make their selling feature an innovative controller then Sony/Microsoft can't take away their selling feature simply through a willingness to lose more money.