Going to jump into the haki discussion since I can just copy-paste something on the haki force-field/offensive/defensive busoushoku: I do like this idea of "harmonized" haki. Ultimately, the damage/attack potential (same for defensive potential) is a combination of the level of haki present and the normal physics (density of the object and force behind the attack). Haki simply exaggerates the normal physics with the magic of touching logia. So for the pain aspects, Luffy is either not putting enough force behind his attack or holding back how much haki he puts into it. For example, when novices first learn to break pieces of wood for karate/taekwondo, it is going to hurt because they don't have enough bone density and or they hesitate and minimize their strike (the faster it breaks the lower the time of force applied to the person's body; the opposite reaction from the wood does not change, but the time of that force can exponentially be decreased). The only example of "mastered busoushoku" that has been shown so far is Sentoumaru and Rayleigh being able to "repel" an attack. Just like judo and some karate techniques, the opponent's momentum is used for offense (taking a defensive technique and immediately making it offensive). Edit: I do not consider the admirals creating an external force field a legitimate example (Oda still only having a rough idea of haki at the time). The Sentoumaru/Rayleigh example is probably a defensive counter technique. Completely different mechanics, although similar visually, to the admirals blocking the frozen mast pieces (which they did not have to do since they are all logia...don't think anything important was below/behind them either). As for haki, I think it is important to re-emphasize the martial arts basis. It takes physical energy to move (busoushoku), but takes essentially no energy to be observant (kenbunshoku). Fujitora is the perfect example of kenbunshoku always being "on". However, kenbunshoku should take minimal "haki energy" because it is simply being observant. "Sensing someone's presence" is a common term used in manga, but it comes down to the real life sounds and environmental changes. I wouldn't bother focusing too much on the Summit War examples because Oda did not have a concrete idea of how he wanted to show haki. I do think haki is much more common in the New World than it is being shown. I can't say for sure, but my gut says Oda was forced into the blackening effect to make it clearer for readers to understand. With the latest chapter, I like Oda being able to go back to not drawing the blackening since the blackening takes away from the scene/panel's aesthetics.