In the world of One Piece, willpower, drive and ambition, and anything synonymous with that are the main qualities one must have to eliminate any obstacle and open doors. It is Luffy's bottomless willpower that makes him charismatic among others and lets him keep pushing back against tough fights until he eventually wins. Haki is the next evolution as the physical manifestation of a person's will. Where once One Piece only treated willpower as a measure of a person's inner strength, now the story treats it as actual tactile strength.
The question is, does it improve One Piece? There are many credible arguments about the positives Haki can offer, but today we offer the opposite. Here are the reasons Haki affects One Piece negatively. Warning: Spoilers Ahead.
It Introduced A Plot Hole With Earlier Big Villains
As the story goes, it turns out every major player in One Piece knows Haki. If they are a big deal in the world, Haki is a prerequisite. Yet, for some reason, earlier villains like Crocodile or Gecko Moria don't have them, despite being members of the Seven Warlords of the Sea - a group that is considered to be part of the toughest and biggest pirates in the world. Then there are the members of the CP9, who are supposed to be the World Government's top assassins. How is it possible for Rob Lucci to be the strongest and most talented agent in the history of CP9, but also don't know how to use Haki?
It makes it obvious that Haki is a retcon. We have arrived at a time where if a villain does not have Haki they are not opponents to be taken seriously. That makes villains like Crocodile and Rob Lucci, who are supposed to have huge reputations, look all the smaller.
Haki Battles Require Less Strategy
Remember the time when Crocodile seems entirely different from any enemy Luffy has faced before because no matter what Luffy does he cannot even touch him? Then Luffy goes back for round 2 only for him to be able to hurt him out of nowhere because Luffy figured out that Crocodile has a weakness with water? That first punch that connected is the most satisfying feeling in the world. But that feeling can never be replicated again with Haki because if that fight happened now instead of then, Luffy does not need to figure things out, all he has to do is punch Crocodile from the start and it will connect. Luffy does not need to find a way to hit The Admirals anymore.
What is the point of having a variety of Devil Fruit powers if everybody already has the ability to bypass those powers? Smoker and Trafalgar Law's Devil Fruits are so strong Vergo should not have a way of beating them, but just because he has the stronger Haki it means he can dominate them. It is almost cheating that The Yonkos don't even need to do anything to counter Law's powers.
There was a time when Luffy encounters a Logia user and he has to figure out how to attack them. Fast forward, if Luffy encounters a Logia-like enemy, Luffy can either just grab them, or master new Haki on the spot.
Haki Is Used To Artificially Speed Up A Character's Strength
Once upon a time when Luffy needs to get stronger, he needed to figure out how to use his rubber body to his advantage. the introduction of gear forms may have been a huge power-up for Luffy, but it is about Luffy being creative, not just about him having Advanced Haki on the spot.
It is hard to swallow that just because Luffy learned what future sight is, that means he can use it after an hour or two of learning what it is. In the biggest power-up in the series, he can now use Advanced Conqueror's Haki and can go toe-to-toe with a Yonko like Kaido because he learned what advanced Conqueror's Haki is 2 seconds ago.
Conqueror's Haki Is Pointless
Advanced Conqueror's Haki is a powerful weapon, but regular Conqueror's Haki is pointless. Sure it will cause any weak-willed opponent to faint, but that opponent does not need any effort to defeat anyway.
When two people with Conqueror's Haki face-off, it's usually a scene of them staring at each other intensely for a few seconds. Sure, it looks cool, but what do either of them accomplish? Neither of them can make the other faint anyway so what's the point?
It Does Not Offer Much Variety
The good thing about Devil Fruit abilities is that there is a wide variety of them. Every time there is a new Devil Fruit User we don't know what to expect and what visuals we will see. There is fun to be had in seeing how one power reacts to another - a surprise when Luffy turns out to be immune to Enel's lightning abilities.
On the other hand, the visual of seeing Haki in action is very repetitive and bland. There is little surprise to be had every time someone turns his fist into metallic black. How boring is it when it turns out that all Vergo can do is Haki?
There are so many types of Devil Fruit abilities, but there are only 3 types of Haki. So there is only so much until it gets tiring seeing people with black body parts and people staring at each other.