So, having played him a few times and even beaten a couple nightlords on him...
Is Executor just a bad character?

His kit is schizophrenic. I feel like they vastly over-estimated the value of his cursed sword deflect, and were afraid of making the rest of his kit good out of fear of making him overpowered. So you have a passive that might as well not exist because you never want it to trigger outside of maybe sepukku, and an ultimate ability that is decent but doesn't gel at all with the core character mechanics or concept so there is no synergy there.
And the cursed sword doesn't even seem to be GOOD. Let me be clear, my problem isn't with the deflects themselves. I beat Sekiro, I know how this works. My problem is that while its very SATISFYING to no-hit a field boss with well timed deflects, in Nightreign this is a losers strategy. You are wasting the most valuable resource in the game: time. You can only use deflect in a separate stance, which makes you slow as molasses and that you have to switch into, and your 'reward' for deflecting enough times is an attack that is only worth using at low levels. But the time that you are facing enemies where the ability to deflect their attacks is actually worthwhile, the charged up blade is nowhere near good enough damage to justify the skill and time investment needed to use it reliably.
I've had better katana guy runs on Duchess and Ironeye than on the character thats supposed to be built around them, because it genuinely feels like he's in the wrong game. Other than the dopemamine hit of the "wow, I'm such a cool gamer!" moment that comes from deflecting a bunch of attacks, the only thing he contributes is a naturally high arcane, which you can use without ever interacting with his defining abilities and indeed feels like you are better off pretending only his ultimate exists most of the time.
What am I missing?