and how would this be possible in this day and age of patent/legal wars?
Well I can imagine:
Sony or MS could have set up a "neutral" game studio just to get their hands on their competitor's hardware. There is probably a good reason why Nintendo does not give each developer the same unit. Probably the most trusted ones get the latest kits. Others might get old kits just to throw the competition off.
And that brings me to another thought. What if the WiiU really is a beast, in the same ballpark of Durango and PS4. But developer bias cant see past the reality of this fact. What I mean is, I can see a studio favoring a particular company, getting everything out of their machine, while with the others, they simply half-ass it and finds excuses to claim that the competition's machine has bottlenecks, or various other issues that hamper similar or better results.