I agree with you there I think he could have done it faster too, they're not that far off in power, I just don't think it would have looked as impressive still because he would have had to be kicking the crap out of the golem. Once Zoro went to take down the golem and cut it in half it took like 5 or 6 cuts to isolate Pica's body, I don't think Sanji's kicks could have separated enough of the golem in 5 or 6 kicks to isolate Pica and I really don't think he could kick Pica's golem in half with a single kick. Overall time shorter amount of hits needed more imo.