Gonzaga totally nullified Mirko's striking. Gonzaga's victory was no fluke. Gonzaga owned the distance in that fight and it was a classic example of effective ring generalship. Gonzaga's high right kick was thrown with excellent timing, precision, and speed. It's not like Gonzaga was getting beaten down by Mirko, closed his eyes, started flailing with strikes, and managed to land one on the button. That kick was thrown with a specific intention.
Mirko is a top fighter. Just look at the competition he has bested. He's not overhyped. Perhaps Gonzaga also belongs in that upper enchelon.