At least 3 times as powerful, if call of duty BO2 runs at 1920x1080 60fps (like the treyarch guy said) while streaming to the gamepad i think that 3x/4x is very realistic.

Lies. 

I see what you did there ;)

About a 50% power increase over the 360 ad PS3, I expect, thanks to the larger RAM pool and more modern GPU. We'll see more advanced shaders and better texture resolution on Wii U compared to the other two.

The CPU isn't the same as the Wii...

I say 3.5x more powerful. People who said between 1 and 2x don't really know that much about the Wii U or what the specs mean. Even IF the CPU ended up being not very good, it would still be more than 2x as powerful due to other factors.

We still don't know the exact specs.

Not enough powerful to make the difference apparent to a normal person that plays the games. The same kind of gap that was present between ps2 and xbox, probably even less.

The fact we don't know the exact specs doesn't disprove my point.  We know enough to warrant it more powerful than the PS3 and 360.