Thank you for such an in-depth review! I think the idea of using the parry for everything would have felt pretty strange on the conrrols side, but I do see where you're coming from. I also appreciete your feedback on the design of the parry, and how you don't have to move as much. It's something I did notice while playing, but there's one thing that makes it make sense to me.
At heart, the game is a speedrunning game. I've said it before, but I believe the challenge of a boss comes from optimizing and chasing it down to get every parry you can, leading to clean parries and a bunch of timesave. (This is also why I removed unblockable attacks.)
I totally get it though. I do hope the design flaws you pointed out don't affect your ratings that much, and I'll be very focused on making sure everything feels cohesive and making sure the player has a reason to move about on a casual playthrough in my next projects.