Enma is a 21 great grade sword that, as stated, drains excessive amounts of Haki from the user. Enma does not give the user power they do not have.
Zoro as seen in Dressrosa was slicing up Pica's golem body with his haki clad swords. This by default shows Zoro can already cut that cliff in Wano if he uses haki and any sword he wants.
The difference between these two situations is that Zoro WANTED to cut Pica and he did, while in Wano Zoro WANTED to just cut a tree and he ended up cutting a whole Cliff. This right here is a failure on Zoro's part for not controlling the sword.
During Alabasta we get a very clear breakdown of what a good sword and and good swordsman is. When a swordsman makes his sword only cut what he wants to cut is when they, the swordsman and the sword, are actually good.
This is demonstrated on numerous ocassions.
Zoro gains the abilty to cut steel WHEN he tells Wado Ichimonji to not cut the leaves and the sword doesn't. The same way his master failed to cut a paper because he chose to not cut the paper.
Zoro argues with Sandai Kitetsu when it cuts too deeply into people the same way he argues with Enma for drawing out too much of his energy
Zoro uses Shusui for the first time and draws out too much power and fails to properly execute an attack he learned in Skypiea and then comments that he has to master the sword which is similar to what he said about getting used to Enma.
Swordsmanship follows intent. Zoro isn't a better swordsman for UNWILLINGLY cutting a cliff WHICH HE COULD ALREADY DO. He is a worse swordsman for letting his sword do what he didn't want to do. Or at the very least, he's just not a good enough swordsman to use this particular sword.
Therefore when Zoro trains himself to become strong enough to STOP THE SWORD from taking his power unwillingly, the entire Haki draining thing will cease to exist. Enma will function exactly the same way as every other sword Zoro has, the same way it did exactly the same amount of Damage as Ame no Habakiri to kaido when Oden used it.
This is what people are missing. Zoro did not master Wado Ichimonji until the Alabasta arc because a Blade isn't a sword until it follows the wielder's exact will. When Zoro managed to get strong enough to master Wado so that his will can make Wado cut steel, this Strength is immediately transferred to his other swords since in the very next arc, he cuts steel once again but with All his swords this time. This is why Enma will no longer drain Zoro's haki after he learns to stop it because all the swords get equalized when Zoro gets strong enough.
Zoro as seen in Dressrosa was slicing up Pica's golem body with his haki clad swords. This by default shows Zoro can already cut that cliff in Wano if he uses haki and any sword he wants.
The difference between these two situations is that Zoro WANTED to cut Pica and he did, while in Wano Zoro WANTED to just cut a tree and he ended up cutting a whole Cliff. This right here is a failure on Zoro's part for not controlling the sword.
During Alabasta we get a very clear breakdown of what a good sword and and good swordsman is. When a swordsman makes his sword only cut what he wants to cut is when they, the swordsman and the sword, are actually good.

This is demonstrated on numerous ocassions.
Zoro gains the abilty to cut steel WHEN he tells Wado Ichimonji to not cut the leaves and the sword doesn't. The same way his master failed to cut a paper because he chose to not cut the paper.
Zoro argues with Sandai Kitetsu when it cuts too deeply into people the same way he argues with Enma for drawing out too much of his energy
Zoro uses Shusui for the first time and draws out too much power and fails to properly execute an attack he learned in Skypiea and then comments that he has to master the sword which is similar to what he said about getting used to Enma.
Swordsmanship follows intent. Zoro isn't a better swordsman for UNWILLINGLY cutting a cliff WHICH HE COULD ALREADY DO. He is a worse swordsman for letting his sword do what he didn't want to do. Or at the very least, he's just not a good enough swordsman to use this particular sword.
Therefore when Zoro trains himself to become strong enough to STOP THE SWORD from taking his power unwillingly, the entire Haki draining thing will cease to exist. Enma will function exactly the same way as every other sword Zoro has, the same way it did exactly the same amount of Damage as Ame no Habakiri to kaido when Oden used it.
This is what people are missing. Zoro did not master Wado Ichimonji until the Alabasta arc because a Blade isn't a sword until it follows the wielder's exact will. When Zoro managed to get strong enough to master Wado so that his will can make Wado cut steel, this Strength is immediately transferred to his other swords since in the very next arc, he cuts steel once again but with All his swords this time. This is why Enma will no longer drain Zoro's haki after he learns to stop it because all the swords get equalized when Zoro gets strong enough.