Man, I've had none of the control issues people are mentioning in the slightest; this very much feels like a faster and more precise iteration of the prior games' combat when it comes to the basic attacking/blocking/dodging/deflecting (and I say that having just finished DS3). Loving the mobility, loving the combat, loving the boss fights.
If I have a complaint, it's that the mob enemies seem (so far) almost entirely un-threatening—to the point where it feels like I'm flipping between two different games when I go from fighting basic mobs to bosses; I'm hopeful this'll improve later on, given that I'm only 7ish hours into the game and have only completed the first two major areas/bosses. In that same vein, though, I also think that—while I love the degree of mobility offered—it feels like the AI haven't been given tools to deal with that increased player mobility; watching enemies toss rocks at me as I dart across rooftops, dangle off the edge to lose aggro, then drop down and assassinate them, feels kind of silly, and is another thing I hope that later game enemy variety will serve to fix; the bosses/mini-bosses have all mitigated this in some way, whether simply through arena design, or through their own abilities, so at the least it hasn't broken the game, but I do feel it trivializes some of the basic exploration that provided so much of the sense of danger and discovery in the Souls games.
With that said, let me reiterate: I'm loving my time with the game, I haven't had any of the control issues others have mentioned, and, as someone who came into Sekiro a bit iffy—worried that I might not be up for another From game quite yet—the game has far exceeded my expectations. So hey, mileage may vary, but I just wanted to toss out a more favorable impression for those still teetering on the fence.
*Edit* Should mention I'm playing on PC; doubt the issues others have mentioned have to do with the supposed performance problems on consoles, but I figure it's worth mentioning regardless.