Look, I am happy, more so than most, with the recent respect TKD is getting in the MMA arena. But the fact is, Pettis didn't really do anything that looked like TKD last night. Right after the fight, in the Heavies forum, people were saying things like "TKD rocks" and "TKD is an exciting style", etc, when TKD really wasn't on display.
To answer your question, and it is an insteresting one, I think it has more to do with Pettis' will to put on a show, as well as his will to use techniques that are outside of the box, that his opponents won't be ready for. I also think that his TKD training and his boxing and MT training has given him a firm understanding of the standup game, to the point that he can pull of the stuff that he does and make it look good. The same with Anderson Silva. Once you experience different stand up styles and theories,you just become really balanced on your feet and you can start creating your own unique style, and trying new things.
So in conclusion, I sort of agree with you, but not completely.
A side note: where did Samaag go?