The thing I loved about Zoro being first mate is that for the entirety of the first half of this manga, everyone was astonished that Zoro was "merely" a subordinate. Having a superpowerful 1st mate in the One Piece universe lends more credit to the captain. Hence why Gol(d) and Silvers were probably such a great tag team.
Hell, Rogers and Rayleigh's first meeting kinda parallels Luffy and Zoro's in that it was simply 2 bros recognizing each other's strength:
"Hey bro, you seem like a cool strong guy. Wanna go fuck the world up?"
"Sounds great, fam"
"Cool"