User blog comment:GrilloSama/Jinbe For 1st Mate/@comment-30281369-20170925205008

You've made some valid points but overall most of Jinbei's actions that may seem first mate quality have been overshadowed by Zoro's by a vast margin.

While it's true Zoro's first calling is that of a swordsman, he had made it clear that he would gladly throw it away if it means getting Luffy closer to his dream to be the King of the Pirates.

Also, Zoro had advised and/or berated Luffy on his actions on multiple times and during most of those times, Luffy took them to heart. The most iconic of these moments imo was the during the aftermath of the Enies Lobby arc, when Zoro insisted that Ussop shouldn't be allowed back on the ship until he apologized.

As far as I know, no other member of the strawhats (including Jinbe) are as capable of influencing Luffy's decision as a Captain through sheer resolve. You can argue that the result would've been the same had any of the other strawhat members attempted the same, however I doubt they would've persuaded Luffy nearly as fast and efficiently as Zoro had.