User blog comment:The ASL Pirates/Will Someone other than Luffy Fight the Strongest Opponent?/@comment-10543621-20150621082454

There's been plenty of occasions where Luffy technically didn't defeat the strongest opponent currently present. These however tend to not be major focal arcs or usually a prelude arc of some sort. Eg like others have mentioned, on Punk Hazard. Thriller bark was quite different as well, where it was really a team effort.

But I think when it comes to the standard crew vs crew format, Luffy has to take out the strongest one. There's just no two ways about it. Luffy has stated that his role as the captain is to be the strongest fighter. Fighting is what he does best and it's the only thing he knows. That's his way of protecting his crew. It would be against his principles if he doesn't take care of the biggest threat.

For a situation to arise where Luffy doesn't take out the strongest adversary present, it's entirely possible, but it'll have to be shown in a logical way. Either because a crew member has a stronger reason to want to fight the said opponent, or Luffy the situation is such that it would be a better outcome if someone else fought said opponent like Luffy is occupied with something else or is incapacitated etc.

For example, if the Strawhats ever clash with Mihawk, obviously Zoro will be the one that fights him. In that case, I'm sure Luffy will be more than happy to step aside, even if Mihawk was the most dangerous threat present. Or if for example, the long ancient dream of Gin re-appearing in the Grandline somehow occurs, and Gin how leads a pirate crew of his own which comes into conflict with the Strawhats, and Sanji wants to be the one to fight Gin, I'm sure Luffy wouldn't mind either.

But the standard major conflicts with antagonists that severely pisses Luffy off, the final major showdown between Luffy and the boss is inevitable.