As for Zoro? Romance down arc was used to humanise him(who was thought as a demon) while showing his care with a little girl he ended up even dedicating one of his attack to(oni giri), showed his resolves(to become WSS at all cost due to a promise to a dead friend he took the sword to fulfil his goal with) as well as defeating the main baddy(Morgan). Baratie arc was used to create the relationship between Zoro and his ultimate goal(Mihawk), arc where Zoro's willpower and resolve was the most highlighted(which was also the origin of Sanji's inspiration to join the group alongside Luffy).
In loguetown, a Kuina looking alike marine was introduced with the goal to take all the meitos who in the end dedicated her goal to defeat Zoro and take his meito with Zoro who at first was always trying to avoid her, but is now not against fighting together in necessary moments with the "gender weakness" brought up by childhood rival/friend(Kuina) being the central topic.
The Whiskey Peak arc was almost entirely dedicated for Zoro(for obvious reasons), alabasta arc was the arc where he first learnt how to cut steel, showed his and Luffy's resolves "winning" a fight with the Bellamy gang by not fighting them with the introduction with the potential final villain who ended up trying to capture them, got 5 fights in skypiea where he first unlocked his long range slashes including fighting the strongest priest, took responsibility for the whole crew to face a shichibukai stronger than the arc antagonist, taking Luffy's burden as well as the whole crew on his own.
Had a sabaody arc dedicated to hype all the supernovas him included, took control of the ryugu palace to engage negociations in hope of the crew leaving the island as soon as possible, defeated the fishmen island main antagonist beginning of the arc, was introduced to a swordsman fire cutter from Wano that he showed interest in since little garten and developed later on in his fight with Ryuma, could push an admiral back, saved the dressrosa kings(Riku), coloseum hero as well as nakama(Usopp), Wano retainers(Kinemon, Kanjuro)'s life, as well as being the origin of the group to stop the birdcage, after training with a top tier, has yet to take any L's since the timeskip, and now is going in a new world island Oda specifically created for their swordsmanship, and as for the funny moments he has plenty for anyone who actually pay attention to his character.
Fodderizing all his opponents without receiving a single scrath is probably the huge change Zoro received between his pre where he was going through fight with sheer power of will after being completely bloodied in major fight and his post-skip self, with the sudden change being the reason why majority is missing his preskip self and i fully understand that, but that's only because those people don't understand Zoro's development.
He trained with a top tier with the mystery behind his left eye scar still being unknown yet. Oda is simply trying to show the result of Zoro's training with a top tier little by little, not only power-wise but also character-wise(he is more serious than Luffy, hence his speech around the "new world....." in Punk Hazard) and for that reason then, Zoro is the character he simply has to hold back as much as possible by making him show his progress little by little(Tashigi wondering about his real power was a hint of this) in a coherant way until his reserved fight(s) happening down the line, most likely in Wano.
That's why he isn't allowed to look bad against Doflamingo level fighters or below, with characters tiers higher than him(Fujitora) being the one used to stop him in these situations

The biased posters understand this, which is why they think they try to downplay him at all cost. Just like how Vergo was supposed to be stronger than Zoro in Punk Hazard. After Zoro fodderized someone on his level(Pica), the speech started to change. Not gonna lie though, i wasn't expecting him to fodderize something at that level myself. I kinda understood why Oda made him crush his opponents in fishmen island and punk hazard to show his return and all, but i was a bit surprised Oda did the same thing in a Shichibukai arc opponent that was supposed to parallel Alabasta where he almost died.
It won't happen in Wano though don't worry. Not only it's an island of swordsmen(so bound for Zoro to get some character progression), but it's involving a yonko with subordinates stronger than Doflamingo. Can't wait for the excuses when Zoro's reserved fight in Wano would be to defeat that level of opponent. I see the same Vergo thing happening after Wano, but don't worry Zoro will surely be bloodied after the fight, so at least you may have something to downplay him when the rest will finally appreciate their missed bloodied pre-skip Zoro again
