Zoro having a Plan is a call back to
Dressrosa 2015 , Where Zoro was trying to Defeat Pica without hurting people in the city. He went through 5 scenarios in his head and decided to go with Plan 5 . Thus creating the Infamous
TACTICS NO. 5 Chapter. Where Zoro displayed armament hardening for the first time, cut mountain sized Pica, became the 2nd person to defeat a full body haki user, and started making people believe he’s stronger than Luffy.