i've mostly focused on katana, so my criticisms will be limited to that. i don't have any issues with braver's skill tree, and i haven't played bow that much.
i think the standing three-PA limit is continuing to hurt the feel of weapons in general. to be precise, there's a couple of weapons where i've felt that one of the three PAs has little to no use—with partisan this is fatal tornado, and with katana it's silverleaf storm. sure, both have some very niche applications depending on the exact size of an attack window, but that's an extremely narrow use case that doesn't make them stand out compared to their alternatives (cleaving scythe and lotus lightning comparatively). because of this, in the majority of play, you don't even have three PAs that are unique and have distinct uses—you have two. it's a big difference!
while the natural response to this is to multi-weapon, katana is one of those weapons that really doesn't feel right to use alongside another weapon's PAs. it has a unique problem—extremely high PP usage—which is solved by a unique solution, the fearless attitude counter, which restores a large amount of PP. the more you use alternate PAs, the fewer opportunities you have to time fearless attitude, and the more difficult it is to keep uptime on those expensive katana PAs. in addition, if you're playing braver, there's probably no PA that gives you better damage value than lotus lightning.
the three-hit combo system is interesting, but not only does it create the pp-hungry problem above (why not just have katana PAs work like calibur streak, and only take PP for the first hit?), i feel there's very little exploration of what such a combo system could achieve. numbers-wise, frames-wise, and hitbox-wise, iris gale is the only PA to have any significant difference between the first, second, and third hits of the PA. there's no sense of value in completing a full combo; it just feels like doing the same thing three times, with a very, very slight increase in damage towards the end. i feel a lot more could've been done with this.
the katana also feels extremely difficult to use in the air. this doesn't just mean chasing high-flying airborne enemies—it's if anything even worse when you're close to the ground, and jumping just a little bit so you can hit a weakspot or a low-flying fuwan. you run out of pp very easily and frequently, and when you do, you have zero aerial mobility options. even your normal attack has very little range and doesn't move you forward at all. you can be looking at a single tiny enemy that's directly in front of you and not be able to hit it without landing and jumping again. in addition, you don't remain floating while fearless attitude is active, and if you activate a fearless attitude counter while in the air, it gets cancelled when you hit the ground—the closer you are to the ground, the worse it is for you. this seems like a pretty bad oversight, and it feels awful. compare force's rod, and how it keeps you floating after you cast a technique for a full second or so so that you can active pp maintain without losing height. and force doesn't even need that!
the frontal counter rule also feels terribly awkward. there's many bosses that are able to hit you from behind even when you're facing them—for example, ard banser and thunder banser doing their forward leap will often go straight over you before hitting you from behind, and nex aelio's spin attack and the daityl's explosions will often hit you from behind if you're aiming at one of its legs. the only other weapon to have a frontal guard is sword, and that has a skill which makes it omnidirectional, so i've never had to deal with this awkwardness before.
this is more of a personal gripe, but the low damage of the counters is also something that doesn't feel great to me. their high dps only reflects that they do a lot of damage compared to the time it takes to execute them--against enemies that aren't bujin, there's no use in getting 621 dps for 0.4 seconds and then going back to normal. twin daggers also have a low damage counter, but that has a secondary purpose—it gap-closes very well. the only katana counter with secondary value is the extremely tricky fearless attitude counter. the others just feel weak.
(it's also worth nothing that the 37-second record is basically matched by a far-from-optimised partisan run on the same enemy. https://www.youtube.com/watch?v=ibgOLqoULoA )
none of these things make the katana a bad weapon overall, but they do make it feel worse than it could, and i don't see a good reason why.