I really loved that they had human scenery for so much of the show. Performers would strut out dressed as the grass of a savannah, or the cooling leaves in a lush jungle. It made everything vibrate with living, breathing movement. The lion's masks were very well executed; the actors didn't wear them over their face, so you could see their expressions, but when they tilted their heads at a certain angle the lion masks would face each other and for a moment you'd forget there was a human involved. It was very cool.
The only real interruption to the story was Timon and Pumbaa. The cartoonish construction of their costumes really clashed with the rest of the costumes; they looked terribly out of place. (I mean, OK, it was like that in the movie too, but it was just so much more blatent in the musical.)