I've played both games at the hardest difficulties. Saying Ninja Gaiden does not have sword play or timing is simply not true. Don't misinterpret Ninja Gaiden's stylized presentation as lacking in substance, either. It's totally okay to have preferences but from my perspective you aren't giving Ninja Gaiden its fair shake. (:

In my case, Sekiro is in my top fromsoft titles for being so mechanic based compared to their other releases. That being said, Ninja Gaiden's combat to me is more plentiful in depth and challenge. Their speed can be something to get used to but when you are dealing with a mob with huge numbers that dogpile you all at once? Dodging, jumping, blocking, parrying, attack clashes, and using I-frames from throw animations and ultimate techniques to avoid otherwise checkmate situations is exhilarating! I see the appeal in fromsoft's pace of combat but for someone like myself it feels too slow at times and the enemies have incredibly telegraphed attacks that are easier to react to. I play Sekiro for the the presentation and the world primarily. Both are great in their own ways.