Finished with the first run and almost done with ch.4 in ng+ as well.
Hands down, Shibata Katsuie was the worst boss in the game. Hell, he is one of the worst things I've ever fought in a game. Not only is he spongy as fuck, his entire moveset is crap especially if he goes bananas and starts chaining his charge moves. Between his massive hp bar and being forced to spend most of your time avoiding his charges, the fight goes on forever.
Bosses in general are one aspect of the game which I found to be much worse than the previous game. It might be my memory is fuzzy since it's been a long time I last played Nioh 1, but I don't remember bosses pulling crap like transitioning from one animation straight into a grab attack. That fucking owl did it 3 times in a row first time I fought him. Like, my dude, you didn't even finish your previous animation and you went straight into the grab one? That being said, I think most yokai bosses are mostly fine in general (tho' the snake, Koji and Osakabe can particularly go fuck themselves. Especially the last one. Nobody liked the dragon fight in the first game, there was no need for another one).
While still on the subject of yokai bosses, I particularly enjoyed the Otakemaru fight. Fought him twice so far, once at the end of the first difficulty and once more in one of those demon scrolls thingies. Good moveset that keeps you on your toes without cloning himself twenty times or charging for half an hour around the map.
Human bosses on the other hand, they straight up cheat and I found none of them fun to fight. Out of ki? No problem, they can do a full combo. Stunlocked? No problem, they can decide they don't want to be anymore and parry you in the middle of a combo, or pull out an attack that is potentially a one shot, especially if they're the later phases of their fight and they pulled out their discount living weapon.
Speaking of Living Weapons, I prefer it to the Yokai shift they have going on. It's not bad, but I found LW to be more fun.
Level design for the main missions varied from good to great, there wasn't a mission that I would say it sucked in terms of layout. Only wish they varied the side missions maps more since there is a lot of reuse, including bringing back at least one map from the first game.
Didn't touch the DLCs yet since I wanted to setup some divine gear first. I got lucky with a random Phoenix Wing drop for the weapon and the rest is WotE with Black Fox mask, tho' the damage bonus given by that one is nothing spectacular and I'm pushing close to 600 magic power. Probably should switch it back to the WotE helmet for the full set since I also have life drain on the weapon and life recovery(amrita absorption) on the armor.
This is pretty much the best I could get on gear so far:
I tried the Onmyo Austerity set as well, but the attack bonus on that was pretty crap, something like ~1% for every 100+ points of magic power. Maybe the version with the Empowered Onmyo will be better.
I used the switchglaive for 98% of the game so far. The moveset is really fun and Empty Retribution and Wildfire Flux destroy pretty much everything now in combination with Carnage and Weakness. I also use Extraction, Protection and Barrier to complete the buff set. The problem I had with it was that it feels lacking until I unlocked a bunch of skills and buffs which lead to a pretty hard time in some parts of the campaign. On a 2nd character that uses the sword and the odachi, the first few missions went a lot smoother and it's not just that I got better at the game, the weapons are much better straight out the gate without much support in terms of skills or needing magic buffs. Doesn't matter now anyway since I have what I need to make it work great.
Tl;dr:
game,
deducted because of crap bosses.