Observation Limitations
Observation Haki predicts future actions as we all know. With Observation Haki you can tell an opponent is going to throw a right kick and follow up with a right uppercut, or you may foresee an opponent is going to run up a tree & follow up with a back-flip and you may foresee your opponent is going to say "I don't intend on dying here"; all of these are foreseen before they happen. Bare in mind that Observation Haki also foresees the future as if the seer doesn't intend and will not under any circumstance intervene; the Observation Haki user never sees how he himself will react.
1. For example, Katakuri foresees that Luffy is going to exclaim "I don't intend on dying here", and then shortly after, Luffy says it exactly as he prophesied. By Katakuri not intervening or doing anything (e.g. kicking his face in), things played out exactly as he foresaw in the spoiler below.
! [qimg]https://i.imgur.com/hr1oWfX.png[/qimg]
2. What else counts as not intervening? Evading attacks. Luffy decides to punch Katakuri; Katakuri has already seen in the future where Luffy will attack. All he has to do is not intervene and simply create holes in his body or move left and right at the very last moment, so there's no reason for Luffy to react differently, and therefore, what Katakuri has foreseen plays out. It's similar to not doing anything. A character sees their opponent will kick them with the right leg, they don't intervene, they let things play out and simply move out the way.
! [qimg]https://i.imgur.com/ykeN3Z2.png[/qimg]
3. Here, it's completely different as he doesn't let things play out as foreseen. He sees what Jigra would say "blah blah blah and shot 2 of your men", but before all that happened, he shot with jelly beans. Bare in mind, he saw all of this play out with his Observation solidifying the notion that things are foreseen from the point of view of not interfering or intervening. Point I want to make here is that by intervening, things may not always go according to plan for either himself or the person he's observing as the next point should prove.
! [qimg]https://i.imgur.com/5oUYP0M.png[/qimg]
4. He's seen the future, he knows Luffy is running to show Big Mom the picture. We know Luffy would just have shown Big Mom the picture anyway without any intervention, but when he intervenes, there's a chance it might fail and chance he might succeed. Remember, it only shows from the perspective of not intervening, so any form of intervention succeeding or failing is as much of a mystery to him as it is for anyone else.
! [qimg]https://i.imgur.com/4AOx6ko.png[/qimg]
5. Here, we can see that Luffy says Katakuri attacks to the side he's going to dodge towards right after his previous attack. Katakuri attacks, sees where Luffy will evade to with his Observation Haki, and when he decides to intervene, he attacks in that direction, but because Luffy has reactions fast enough to respond to Katakuri's attacks, things don't play out the way Katakuri wants. Again, Bare in mind Observation Haki allows the seer to view things as if they're not going to intervene, so the success of any form of intervention depends on how quickly the opponent can react to a change and the speed of the Observation user.
! [qimg]https://i.imgur.com/iHcwoJC.png[/qimg][qimg]https://i.imgur.com/9BzC6hy.png[/qimg]/ Another point this makes is that the user cannot user Observation Haki when intervening because committing to an attack + Observation Haki require the entirety of one's focus, so it's impossible.
- Long story short, this is how Observation Haki works - Uses Observation > Attacks (intervene)/Defend(Dodge) > Uses Observation again > Attacks (Intervene)/Defends (Dodge) - over and over again until they battle is concluded.
Reactions & No Reactions
So, while Katakuri can see into the future (as with all other Observation users), should the opponent possess fast reaction abilities, they can always evade attacks and as long as the Observation user intervenes, the future doesn't play out as they foresaw exactly. It indicates that Jigra could possibly have survived had he possessed the reactions and was cautious enough to be ready to respond to the change in setting; unlike Jigra, Sanji who was alert to his predicament and had his guard up was ready to react to any changes, and that was why he was able to evade Katakuri's shot - not so much a failure of Observation Haki.
This also enlightens one as to the nature of evading (not inciting a reaction) and attacking (inciting a reaction). Evasions seem to have a greater chances of success because things play out as foreseen, and all the Observation user has to do is simply move out the way while, in the case of the Observation Haki intervening (attacking), it may make out that Observation Haki is useless for attacking since the opponent can just move out the way if they possess good reactions.
Observation Haki though may not guarantee any intervention in regards to attacking successful (or even in evading as that's also down to speed & reaction), it more or less still sets up how one should follow up with their next attack and allows one to incessantly pile on enough pressure against their opponent until they falter and leave themselves open for a fatal blow. It's better to know your opponent will move to the right before your attacks end than only after it ends where you have to wait for your opponent to manoeuvre before you do, because then, you can setup your next attack before they're ready to react.
Heated Battle
When one attacks, there's only so far into the future that one can see because they're in a heated battle as there's a chain of reactions being incited when an Observation Haki user is on the offensive. They'll like be seeing milliseconds into the future due to the pace of the fight and the moment they intervene into what they've foreseen, their opponent will likely react like image 5 showcases if they possess the speed to do so.
The reason evading attacks always seem to have more success than attacking with Observation Haki is because evading attacks doesn't incite a new reaction from the opponent, they're just attacking with barrages until they hit without much calculation. You see your opponent will stab your left arm with a spear, you don't charge at them to incite a reaction, you wait for the spear to just about hit, foresee and and evade, and everything plays out as foreseen.
While Observation Haki is a powerful tool, when you have an opponent that has great reflexes like Luffy (in fact this might be indicating to us how great Luffy's reflexes are), there's a margin of error for the Observation Haki user on the offensive and this increases the greater the reactive speed of the opponent. It's also enhanced by the fact that Luffy is rubber, therefore, he's very flexible as we see and can perform unorthodox evasive manoevures. Anyone else might have been killed in image 5.5 or broken their necks at the very least, but he's rubber.
How Does Luffy Overcome Katakuri
There's also something that needs to be pointed out regarding Katakuri. Without his Logia-esque ability, he wouldn't be this difficult to fight. The big issue here is take someone like Luffy, he can't create holes in his body, therefore, when he avoids attacks, he has to move to the right, left, jump, etc. He has to dodge by moving and this leaves him vulnerable especially if not extremely agile and flexible as seen when Katakuri tries to stab Luffy's head, and Luffy slams his own head down to end his momentum and change direction.
This is what is terrifying about Katakuri, he on the other hand can stay on 1 spot and avoid all attacks meaning it becomes rather difficult to get him flat footed as he can evade all things from standing on the spot. How do you defeat someone who can literally dodge any attack without moving? You punch and he makes a hole in his body (think of the size of Katakuri's body compared to Luffy's fist and the implications). In order to hit Katakuri while he's composed, there's really only 3 things that come to mind:
- To either become faster than Katakuri - meaning Luffy must be fast enough to throw attacks faster than Katakuri can create holes in his body - Probably requires a power-up.
- Other solution is Luffy has to use giant sized attacks that are too big for Katakuri to simply create a hole and those attacks tend to be slow. Katakuri would see it coming from a mile away.
- Final serious solution is disrupt his CoO by King's Haki assuming it can do that - it's somewhat hinted as being able to do that.
It's no surprise this guy hasn't been defeated or hit in a long time. It might not be that he's even stronger than his opponents, he's just so skilled at evading attacks thanks to his ability and he's so huge too standing at 5 meters tall (which is ironically an advantage as a Logia/Unique Paramecia) that the only way to defeat him or remotely hit him is to have attacks that are too big for him to evade and equally fast. There aren't many people who have these qualities besides Big Mom and Kaido as they're giants with enormouse sized fists - and even with a fist her size, whose' to say he can create a hole in his cavity that's as big as a gaint's fist since Mochi has elastic properties to begin with. So, it really would take something special to defeat Katakuri.
Damn xD Well formatted lol. But anyways, I was already aware CoO sees a future that doesnt involve the user in the equation. We found that out the moment Kata was introduced. Im mainly confused about how complicated it can get. What a user sees is obviously not set in stone since they can alter it if they so choose. So technically Oda has gone into the realm of infinite realities because whats seen could be change and thus branch out into different realities. Lets assume you have 2 users like Kata. You have one read the future, but then the future gets read by the other user and repeat. It turns into this loop of everchanging possibilities. I think the reason the Minks ability to hide their presence from CoO was to counter this loop. You also mentioned speed to counter CoO somewhere in your post. We've known that since Amazon Lily. I kinda just skimmed the post but Ill re read what you wrote.0
Edit: But maybe there might be a level of CoO where everything you see is whats set in stone. Maybe its what Shirley has. But its kinda pointless in battle since you have no clue when itll happen or what leads tp it.