What pain? Kaidou couldn't do better, only retarded Zorofans try to make jokes out of it.
Disappointed that Oda didn't give due spotlight to Sanji's strongest attack.
I doubt people would have been disappointed if Sanji had done it alone, what sucked was Sanji landing this attack next to Franky and Bonney, which made it seem like the attack wasn't appropriately strong.
Suppose Luffy had just asked only Sanji to kick him, and then sent Gorosei into space, no one would have been disappointed