After getting used to the controls and certain oddities of the design, the game is really, really good. Even fighting multiple enemies isn't that bad when you no longer have to rely on locked camera. Probably a 9/10 for me, and I rate very few games that high. One of the best games I've played for sure. There are deceptively many ways to go about the combat with all the different prosthetic upgrades and combat arts as well, but none of them are required either. I wish you could have more than one combat art equipped though, there are lots of cool ones that are hard to justify equipping because you're locked out of the best ones then.
There's a very real feel of "mastering the combat", which feels pretty gratifying. It's like you level up your skill instead of your character. Instead of the typical RPG thing of easily defeating enemies that used to be hard because you're 20 levels higher now, you're easily defeating enemies that used to be hard because you've gotten better at the game. The fight that really taught me how to play Sekiro was the first Genichiro fight. Took me a little over an hour of trying to beat him, but after I beat him, I killed virtually every boss on the first or second try.
The only true weakness of the game is the plot. It's kind of just there, and it's told in a pretty off-handed way by static NPCs. A game with Sekiro's mechanics and a RPG style plot+quests would be something truly amazing.