The number of unsubstantiated reactions to this news is ridiculous.
So much has to do with optimization of hardware.
We have someone on these boards (wsippel) who has direct behind-the-scenes knowledge of middleware support the Wii U is receiving, and wsippel specifically mentioned that after initial optimization, the current Wii U CPU in devkits alone performs at the very least "on par" and in some areas "much better" than Xbox 360's CPU. With more optimization, this will only end up becoming better. The Wii U CPU is not the same as the 360 CPU even though they may be different. When a developer cuts and pastes the code from a 360 title to a Wii U title, it is not accounting for optimization. This can easily create a "slower" game because the 360 incorporate audio and I/O functions into Xenos. The Wii U has its own dedicated audio DSP and I/O ARM processor to handle those tasks. So, that alone is a big problem. If developers are making ports and not ground up games, they are not going to reconfigure every single line of code just to get a port up and running. The quick and easy way will always win out in the end.
Yet, according to wsippel, the CPU could have initially appeared to be worse. But once optimized it ended up becoming at least as good while outperofming the 360 CPU in some areas. Outperforming DOES NOT EQUAL "worse" than 360. It means Outperforming! lol
Optimizations alone can account of this. The tools Nintendo gives developers keep getting better and better (that is, accounting for more optimization of hardware) and there are insider reports (legit insider reports) that the hardware is still being more and more optimized.
Mix this with at the very least RAM that is twice as much as the 360/PS3 (as confirmed by multiple insider sources such as lherre who is a developer with access to Wii U kits...Purportedly Nintendo is targeting above that range however) and a much newer, more capable GPU (early devkits had an RV700 level GPU in likely to set an expectation level) than either the 360 or PS3 can handle,
and all that any logical sane individual can say is that if a developer says the Wii U is weaker than either the 360 or PS3, or even simply "on par" on a technical level (not what you see on the screen), they are doing a poor job developing for that system. Period.
Optimization is huge when it comes to porting.
And first party or exclusive efforts, generally, will show a system off the most.
Many Gamecube games looks "on par" with PS2 titles, in some cases worse due to compressed audio and video cutscenes. But when built from the ground up, a game could really shine on that system: case in point was Resident Evil 4.
This generation of HD consoles, we had titles like Killzone 2 and 3 which were optimized for the PS3, God of War 3, Uncharted 2/3, etc... on PS3 and Gears 2/3, third party tools that showed the best multiplat titles, that were all optimized on the 360.
When a game is optimized on the Wii U -- or any other next gen console for that matter -- it will look better than what is currently out there on the PS3/360
But in this day and age, where HD graphics have their set their own standard, it doesn't mean much. The average gamer can tell the difference between a PS2 and PS3 game, but no matter how much better the graphics on PS4 end up looking, the difference won't be as large simple because of the HD effect.
I can't believe how little understood this basic concept is. This is a video game enthusiast forum, right? So why don't people take the time to understand something as simple as this? Here we are zoning into 2000 posts on some reporting (I used to be a news editor; I know how little work can go into reporting news) that can be easily explained by something as simple as developers porting with un-optimized code??
Its ridiculous!
In the end, the Wii U system likely is only 2-3x more powerful than the Xbo 360/PS3 (the GPU alone will be much newer and capable of more effects) but its not going to be a powerhouse. That much we know. But the Xbox 360 was many, many times more powerful than the Xbox 1, yet developers only "cutting and pasting" their games resulted in titles like Gun at launch.