I have to disagree, Luffy was having a major breakdown.
It wasn't supposed to be pretty, it was supposed to make you unconfortable.
I don't see how they could have done it any better.
It has nothing to do with that. Those weird squiggly movements were distracting and annoying. I couldn't connect to Luffy at all as all I could see was him trashing around and shaking his ass. It would have been much more ugly and heart-breaking and epic if we could see his face as he beat it to the floor.