Not only that, but what specs are important?  Most people who play games have no clue on what game development consists of, how the hardware actually works, and what actually causes bottlenecks in performance.  They just look at stats like.. 8 core....3.2ghz....8 gb ram....blah blah...and get overly excited.  There is more to it than that, much more.

Nintendo has always been good at engineering their systems to be dedicated gaming systems.  This allows them to expose registers that can be manipulated to allow for the hardware to perfrom tasks, at a rate that any software could only dream of.  Also, when a system is tailored for gaming, you don't have the overhead that is needed when it is a jack of all trades (like a PC).

Now, one important thing people need to look at, in terms of the Wii U, is the GPU.  We know that the CPU isn't as powerful as the PS4 or Xbox One, but does that truly matter in terms of gaming?  Do people on these forums understand what the CPU does in terms of games?  

Now, you have to issue to draw calls with the cpu, and the dispatch calls as well (dispatch is for doing computations on the GPU).  This is where some bottlenecks can really occur, due to bus speeds, and other factors.  Most engines batch their draw calls, so they can have a ton of assets, with a minimal amount of draw calls.

Physics, Particles, Entity Updates, etc, are done on the CPU, but, they can also be done on the GPU, and that is where I believe Nintendo is getting thi performance boost from.  The goal is to have the GPU always running (which usually never happens) and the CPU always running.  That is the goal of system optimization.  If they unload Physics, Particles, and the Entity Updates onto the GPU, that frees up the CPU for other tasks, and keeps the GPU busy inbetween the draw calls.  Now, doing this work on the GPU isn't an easy task for programmers.  Creating a compute shader seems easy, but making sure you are taking advantage of the parallel nature of the GPU, and keeping the algorithm from becoming serial can be a pain.  Poor synchronization can really hamper a concurrent application.

Another thing that really helps, is the memory transfer rate to the GPU is fast.  I read an article that compared the bandwidth with the XBox One, and the Wii U had a 4 GB advantage.  They didn't reference the PS4 in the article.  That is another reason they can hit 1080p on almost all their games, and 60fps.

Many consumers do not dig deeper into the numbers, and just always assume that bigger means better.  But, sometimes that is not the case.  Do some research on the performance of iPhone 6, and the top of the line Android Phones released this year, and you will see that the iPhone (with the smaller numbers on its spec) out performs them in every benchmark on the CPU, and destroys them on every benchmark for the CPU.  The article I read, placed the blame on the Android OS, stating that it doesn't take advantage of the hardware that it runs on.  That could raise the question of whether these console OS's are affecing performance of the games as well?

Many factors, but, in the TLDR, specs don't always matter, it is how those hardware pieces are engineered, and how they work together.  It is also how the developers approach and take advantage of the hardware.