For the "King is going to chop Sanji's leg off" argument
Luffy needed Rayleigh to learn haki, Sanji unlocked it by himself
I guess reaching FS and Advanced CoA out of nowhere is more than a possibility
Btw it's an argument that doesn't make any sense. King is stronger than Sanji as Kaku or Mr 1 were stronger than Zoro. Then asspull and win.
At least the RS might nullify a part of King powers and make everything more logical :cheers: