I just quit ballet after 13 years because I had to start wearing toe shoes. Toe shoes eventually ruin your toes so terribly it makes walking, let alone a martial art, incredibly difficult.
But, ballet worked wonders with my footwork and flexibility. Even if you dont take ballet, i would strongly reccommend some of the stretches. Not only do they stretch, they actually add strength. Your leg muscels can become so developed just from stretches. They also work back muscles, which not a lot of traditional stretches do. I am one of the only people in my dojang able to do the scorpion kick or the reverse header. Several dance techniques strongly resemble internal arts. i dont know circular stepping, but a pirouette is a large leg extension either in the air on at a standstill.