Don't know about ML, but at NF only the Zoro fans say otherwise (lolExtravlad) and for your statement no he's getting low diff'ed just like how Clone Doffy Low diffed luffy.
Like Roronoa Zoro said, gets updated. The clone got one shoted by a low-mid level attack from Luffy. The only reason Luffy even struggles yet is because he doesn't want to hit Bellamy. When the Bellamy matter will be resolved, people will be singing a different tune, i guarantee it.
Only way for Luffy to defeat Doffy is by either the damage Law has done or Big Mom/Kaidou. Doffy's hype is too great to be simply defeated by Luffy.
You'll see by yourself then. Law is done for already. Who do you think will defeat him?
Crocodile low diffed Luffy as well twice because he couldn't hit a logia and lacked a lot of knowledge. Under these circumstances Zoro would lose easily yes, but put Zoro in the same place as Luffy(in a 3rd fight, with water, knowledge and all the advantages) and i guarantee you Zoro would win as well(well discounting the poison). The poison was the only thing that made the third fight even a match when you know how dominating Luffy was in that battle
Luffy and Zoro were closer in power than you think. Before the Enel battle, Luffy clashed with Wiper in a battle that ended up in a stalemate and multiple injuries on both side. Same Wiper clashed equally with Zoro on multiple occasions and Zoro ended up defeating the strongest priest. The thing around Enel is different though. If Luffy wasn't made of Rubber(Enel's natural enemy), he would have lost easily as well. When Luffy noticed that Zoro lost he couldn't believe it. He said
how could something like this happen when YOU were here? That sentence alone says everything. What allowed Luffy to win when Zoro couldn't is something called match-up advantage. Even Oda himself said that later in an SBS that normally, Enel was levels apart Luffy during that saga and Luffy was only lucky of being made of rubber
Only reasonable part although i think Zoro could have pushed him to mid(high) difficulty. Luffy clearly seperated himself from Zoro during that saga but that was mainly because of the power-up of gears(something Luffy didn't have before). He decided to do all what he could to become stronger(even using a technique sacrificing his lifespan) after losing to Kuzan. However, Zoro wasn't that far apart. What people sorely mistake is that the douriki were representing the fighting strength of the opponents, not Zoro's/Luffy's/Sanji's. While Lucci had close to double the fighting strength of Kaku, Luffy was close to lose against Lucci when Zoro defeated Kaku much more easily. When the power-up of Asura(trippling his potential as a swordsman) came, it was a one shot even but i think he wasn't controlling Asura well during that period in time, so yes Lucci would have won in the end, but not as easily as you make it out to be
Did Luffy even fight base Moria? Because if you're referring to base Moria, i'm not sure what you mean here and both Oz and Asgard Moria's fighting strength was greater than Luffy's as well(although Asgard mode was a self-destructive mode)
See the pattern? If Luffy high diffs the main boss, Zoro's getting Low diff'ed by him. Only exception here is Hody which he was completely horrific. Having only pushed Luffy to low diff by fighting under water.
The only opponent Luffy defeated fair and square(and by fair and square i mean strength-wise and not a natural advantage or circonstance like Luffy had with Crocodile/Enel) that Zoro couldn't so far is Lucci and that difference in strength happened because Luffy decided to use a technique that sacrificed his lifespan to become stronger. The importance of gears dimished with time however