Yes, his back appears to arch a bit too much in the six, like he's disengaging the abdominals--but they're gorgeous batterie nonetheless.
A lot of dancers will cross the legs immediately in changement --on the way up -- but his open in the air. The quatres are particularly wide. Personally, I like the way the open, close, open, close technique looks. I've been practicing changements with an immediate change on the way up, since that's what my teacher prefers, and I feel it will help me develop toward entrechat six. Yet I don't like the way it looks as much. I've noticed that the SAB-trained dancers cross on the way up as well.
What do you all prefer, and for what reason. I can think of pros and cons of each technique and am wondering what would be preferable for an audition. Would it really depend on the speed of the combination?