i get the feeling the kaidou arc won't take off until after the reverie. that is because i think he is planning on doing something to spark the huge war he wants so badly. i think big mom might make luffy change objectives but i'm not sure if she is going to get taken down though. maybe luffy and friends cause major damage to her and her alliance which allows blackbeard to take her down or something.
yeah he might be leaving to make preparations or something for the war against kaido. next time we see him he might show up with luffy's alliance against kaido.Speaking of Law, I think he might be done in the story for the time being.