Developers of Cave Story say Wii U is the most powerful system Nintendo ever made.
This is a textbook example of Double Speak. Even the most negative anti-Nintendo analyst ever doubted the Wii U was going to be more powerful than the Wii. The Wii is currently Nintendo's most powerful system (unless the 3DS is more powerful, which it may be), but the Wii is extremely weak by current gen standards, so the bar is very low and for the Wii U to rise above that bar and become Nintendo's most powerful system isn't really saying much.
What we all really want to hear is that the Wii U is the most powerful console ever made by ANYONE, but that's not what we're hearing. So the uncertainty over whether or not the Wii U is more powerful than the PS360 still lingers on.