Given the way I've always played the Souls series (and Bloodborne) a lot of what other people see as omissions don't really feel like it to me.
I've played DS1, DS2, Bloodborne, and DS3, and DS3 was the only one I didn't finish, because the From "formula" had started to feel stale by that point. Across the board, though, I played all those games in a very similar way: I specced into dexterity and health, and I tended to use either fast swords or the occasional scythe / polearm. I always took it slowly, I never summoned, and I'd try to parry absolutely everything I could.
In Sekiro, I don't miss having RPG-style stats, because I'd got so used to my way of playing Souls games that it felt like going through the motions building the same way every time. Lack of imagination on my part? Probably, but my approach always felt like it fit with the Souls fiction; I was a lone adventurer braving a supremely hostile world, so it made sense to be calm, cautious, and ready with the steel.
By the same token, I don't miss the different weapons much, because the katana lends itself perfectly to my established play style. Stay mobile, bait attacks, and parry everything.
In terms of world design and atmosphere, Sekiro obviously isn't as dank and dingy as a Dark Souls 1, but I don't think it needs to be. Dark Souls always seemed to me to be a corrupted vision of medieval European fantasy, and Sekiro is... a corrupted version of Japanese feudal fantasy. Yes, the enemies aren't as outlandish, but the locales and level design are both striking enough to let Sekiro stand on its own terms. People had impossible expectations if they thought Sekiro was going to be full of dragons and aliens.
The stealth is something I'm still not quite decided on. It's obviously very heavily emphasised - probably mandatory for some of the big arena areas you have to traverse. It's also rewarding to practice well. The AI is probably too easy to exploit, though; those big arenas never feel like a test of your stealth skills or planning, because you can escape and 'reset' at any time, with no real penalty. Unlike Souls games, where a single Black Knight would chase you to the ends of the earth, an armoured general in Sekiro will shrug his shoulders and quit looking for you if you so much as zip up into a tree. That can make big areas feel like tests of patience more than anything else.
Otherwise, I think the combat is From's best because it aligns with the way I've always played their games, and then iterates and improves on it. Where DS bosses were about learning to use your limited tools to take down something insurmountable (mostly,) the bosses in Sekiro have a wide range of offensive and defensive options... but so do you. They thrust, you Mikiri counter. They sweep, you dive kick. They swipe, you parry. These battles might be extremely hard, but they feel fresh.
The two things I dislike about Sekiro so far are also things I had a problem with in previous From games. The tracking and magnetising effect on some enemies' attacks is patently unfair and very silly to look at. The early ogre is an obvious offender, with his magic grab that catches you from fifteen feet away and pulls you into the animation, but he's not the only one. The other problem is spirit emblems. In Bloodborne, I remember getting stuck on a boss - it was probably Ebrietas - and running out of bullets or vials. Queue a fifteen minute farming session to get more, before I could try the boss again. The equivalent hasn't happened in Sekiro yet, but I can see it happening in the near future. I'll run out of spirit emblems and I'll have to go and farm for sen to buy more, or I'll have to have stored a load of coin pouches previously with this eventuality in mind. I didn't understand what that process added to the game in Bloodborne, and I still don't understand it here; it's unnecessary busy work.
EDIT: Forgot to add, I also played Nioh. Loved the combat in that game, but found the world and enemy variety really uninspiring after about ten or fifteen hours, and quit. That was gutting, because the two Nioh tests I played were my favourite gaming experiences in a long time, but the full game didn't build on those in any serious way beyond more loot, more of the same enemies, and increasingly dull levels.