For a while, there was some criticism regarding his role this arc given Gaban was getting lots of spotlight whilst Sanji hadn't done too much on his own, but Oda used that as great setup for what's currently going on. Sanji's done great, saving Robin, beating Killingham before, facing Imu albeit losing and now rushing in to save the giant kids and beat amped up Killingham. Very likely that CoC is incoming, so fantastic stuff from him. It helps that there isn't too much going on anymore, so we can hopefully just get a good fight from him and a pivotal moment for his journey supporting Luffy.