I'm having an absolute blast with Nioh, it's so good. I actually love the non-continuous structure of the game. Being able to replay a mission and nailing it without a single death, including the boss that killed you 10+ times the first round, feels great. Perhaps it will start to feel repetitive further down the line but right now it's excellent.
Enemy and world design aren't on the same level as Soulsborne games but certainly not bad. It does feel like the bosses so far have been easier to master due to a more limited move set compared to Soulsborne games (certainly compared to Bloodborne and DS3). They can punish you until you get the patterns down, after which it's plain sailing. Though I'm still expecting greater challenges ahead obviously.