I performed this antenna mod and I can attest:
It doesn't work! Don't do it!
I replaced both of the stock 5ghz antennas with
these, and the reception was ~20% worse than before.
I tried moving them around (vertical, horizontal, different height) but the results were the same.
I installed them directly to the card and did not solder anything.
I am guessing the original 5ghz antennas that come in the WiiU are already optimized for their purpose.
That being said, I still think reception through walls can be improved with
directional antennas.