Many of the Masters that you see getting their asses handed to them dont usually get punched in the face repeatedly, Im sure if a calm and focused expert wouldnt do that bad, Kung Fu is just another art that does not work well with todays MMA, as todays MMA is no longer about styles, yet adaptation.
Theres tons of other Martial arts that dont work well with Kung Fu, why you gotta hate on Kung Fu. MMA has had 15 years to sort out which art works best, and we found out within the first 3 years that no ONE art works well. You cant really say BJJ alone or Boxing alone works well because theyre are both ultimately missing their opposite sides.
Kung Fu is mostly a wide striking art, sure it would work against average people or other Kung Fu experts that utilize strictly Kung Fu, but in a sport where someone knows 9 different Arts, one descipline isnt going to get you anywhere.