I am one of those who think that it is difficult for the Marines to have conquerors because they are always subordinated to the chain of command. On the contrary, a conqueror is there to stand at the top. That's why we've seen very few conquerors, in fact at the moment I'm not even convinced about Garp and Sengoku.
Fujitora, having grown up outside the Navy and seems to be more on his game than anything else, being able to blind himself, may be worthy of the King's Haki. But I wouldn't dare to say it at this point either.