How different are they from what people perceived? They didn't do anything worth a dime in the grand scheme of things. You don't get to be YC level just because you can throw an attack at an admiral. That's overwank ultra max pro right there. There guys are supposed to be considerably weaker than Sabo or Sabo should be considerably stronger than them like every other notable Number 2 should, which means they are way below pre-Mera Sabo, who's weaker than post-Mera Sabo, who, in turn, failed to make Fujitora take him seriously despite Fujitora's lack of effective attacks for him.
Jozu had a death match with a much less restricted admiral, and lasted longer than these 3 bums combined. Kuzan is deadlier to engange in close quarter than either GB or Fujitora in a one-on-one, and Jozu refused to go down until he was distracted—granted his ability works well against freezing. Marco completely blocked and laughed off an attack that's meant to kill WB. Let's not even joke about comparing these guys. Do you think Morley lasts longer than Cracker against Kuzan? Good luck with that lmao.
Rev army is a bunch of civilians who happened to have extraordinary talents working together. These guys aren't highly ambitious people with unparalleled potential trying to rule over the world like pirates. You have to be generous to even consider Iva a YC2, forget these guys.