Uhh, zoros ambition is to be WSS. The current WSS already told luffy and zoro that pirate king>WSS Zoro wants to be a world class hobbyist. He knows its easier to be the strongest swordsman than it is to just be the strongest It was easy for Mihawk because his competition was Shanks. For Zoro will be much harder. Where is the ambition in finding just a treasure?
