Like I said in another thread Kampmann and Ellenberger are more dangerous fights for GSP because they have more tools. I don't really think it is fair to compare Hendricks to the guys you are comparing him to though he is a better wrestler than all of them but Kos and he trashed Kos standing when he wasn't being eye gouged.
Kampmann's head movement is fine. He is good at slipping punches; it is his footwork that is terrible.
GSP didn't tool Kos the second time around or Shields wrestling and Fitch got tooled wrestling by BJ so I don't think you can act as though he is some amazing wrestler. Guys like Ellenberger and Hendricks should be able to stop most of his takedowns.