AI and goto maki are easily some of the best (and most underratted) dancers in j-pop.
http://youtu.be/ptm8zBdawY0?t=1m38s moves in this vid aren't flashy but the way she's able to stomp around with such precision wearing HEELS is great. i would post an example for AI but her concerts got deleted from youtube again -__-
as for kumi her dancing tends to get overshadowed by her extravagant stage and concert outfits. if we were having this convo in 05/06 it would be a different story lol