On another note I haven't been to impressed with the full body haki. Both people we've seen with it were defeated or killed while using it. Idk maybe that's just me being technical, but still it's hard not to notice.
Maybe concentrating it at one point like luffy does is stronger.
Plus we don't see shanks or Rayleigh use full-body haki, I know that doesn't mean they don't in a real fight. But I belive those two probably have the best mastery over haki right now. So if they don't think it's important maybe it's not all it looks to be.