I don't know if it means something, but I noticed that on Pikmin 3 you can divide your squad in 3 groups that can work on different places all at the same time. Maybe it has to do with the 3 cores available.

It's probably more like Dreamcast.

I'm not sure why this is a thing. One of the Dynasty Warriors developers said quite awhile back that getting one of these games working on the Wii U is a challenge specifically because of the CPU. That's pretty much all we need to know about that.

The strengths of the Wii U are elsewhere.

Going by the thread' title, the WiiU's CPU is still weak to a smaller degree, no?

So agreeing with the OP is drive-by? It's pretty clear since launch that the wii U is way more powerful than the wii, the wii could not pull off games like wonderful 101 or pikmin 3.

Cross platform high power games. Seeing how they peform on each platform would be the better indication of relative power of each system. 

WiiU's CPU isn't weak at all. It's solid fact that we're talking about a well balanced and wisely engineered product, with a lot of potential to improve.
But yeah, Hyrule Warriors doesn't prove it. It's a nice looking game, alright, and most importantly it's fun.
I wouldn't call the Espresso powerful, I'd rather say it's smart: thanks to its architecture and optimization it can achieve a lot, with little "raw power".
People claiming that the Wii U is just a 3-core Wii, or that it's on par with ps3/x360 are delirious.
Overall I'd say the Wii U is waaay more powerful and capable than most people think, but Hyrule Warriors doesn't show this in any way. Nor does it need to: it's a fun game, looks nice, plays good, that's its job.
Besides, noone should expect a Warriors game to push any kind of boundaries when it comes to visuals. It's just not their thing. Nintendo on the other hand has already proved how capable the system can be with it's fp games, and even lazy ports can prove this point, by working on the console with no optimization at all, despite the different architecture (x86/powerpc).

Rather, it's all warriors use the warrior script. All lancers use the lancer script. Boos 1 uses the boss 1 script. Boss 2 uses the boss 2 script. Etc. It's really not that complicated to understand. 

I get the OP's point, but unfortunately, crowd AI has been long developed for before Hyrule Warriors, and can be done on a fraction of what it seems like it requires in terms of CPU power.

Quite honestly, Pikmin 3 is, so far, the best example of CPU power. Not only are there 100 pikmin that can be running around ALL POTENTIALLY DOING INDIVIDUAL THINGS, but each one also has to follow PATH FINDING ROUTINES (since flying pikmin take different routes, for example). Crowd AI doesn't work in Pikmin 3 very effectively since you have CONTROL OVER ASSIGNING TASKS. When you have 10 carrying a fruit, another 10 carrying an enemy, 5 farming spicy berries, a captain with pikmin heading to a waypoint, another captain camping a "multi-fruit" (grapes) or build pile that has pikmin running back and forth, and you're battling enemies actively using the rest, there's a lot to keep track of, and the CPU does this just fine.

Didn't Pikmin 1 and 2 on Gamecube also have 100 Pikmin running around at once though?

And based on clock speed and core count alone, Espresso (Wii U CPU) should be about 7.5 times more powerful than Gekko (GCN CPU) and that's before you factor in the 12-fold cache increase.