User blog comment:JapaneseOPfan/Luffy vs Smoker,Coby/@comment-3242083-20110121172445/@comment-3242083-20110121173601

Well, Smoker would have to develop the "anti-haki" like Akainu, Aokiji and Kizaru. They got sliced in the neck and impaled by haki imbued attacks, but still reformed like usual.

Thats why I said that the confrontation with Hancock could be the impulse for him to train that "anti-haki" (or whatever it is) to eliminate that weakness. It would be no surprise, since we could already witness Smoker's skills increasing over time (like becoming smoke by reflex, flying like a rocket instead of just floating around etc).