*facepalm* The CPU size has very little to do with how powerful it actually is. Have you seen the actual size of the Core i7 3770? Pretty damn small. And yet 10X more powerful than what is in the 360. No, the reason why the physics engine isn't in Maden NFL 13 is becasue either A) They were strapped for time or B) (as the rumor goes) EA is pissy at Nintendo and stripped features in a hissy fit.
Well, the Wii U itself is small, which makes running at higher clockrates more difficult, which results in a weaker CPU.