Agreed, it can be the best final boss from MIyazaki games:
-False King was good in DeS, and the soulsucker skill made him really terrifying, but it was fairly easy to kill if using light armor.
-Gwyn was an intense fight and a "fast" boss was something hard to fight in DkS I, but it was also really easy to exploit (parries, iron flesh works wonders against him).
-Gehrman was like fighting a strong "normal" hunter, but having a fight against a "small" enemy means no fighting against the camera, and the music was really good. A good fight after lots of "big enemy bad camera" fights.
-Soul of Cinder was far better than any previous Souls boss IMO, it has the best lore and a really crazy moveset. Again, normal-sized enemy in a empty arena is what this games benefits the most from. Sadly is kind of easy.
-Sekiro's final boss highly rewards not running and being all the time on the offensive/counter-attack position. He recovers posture really slowly so it's not another fight of endurance, it's about making a string of good decisions. And it's really rewarding.