I came across Create Thrall when I was making my character for Curse of Strahd. I decided to go with Goolock for thematic reasons, and made a list of every way to incapacitate someone in 5e, even knowing the campaign doesn't get to level 14. Hypnotic Gaze still stands out to me as the clear winner for being recyclable and also a really strong ability on its own, as well as not (RAW) breaking Sanctuary.
I still think Goolock is weak (this can't affect non-humanoids, which I find a little disappointing), but nowhere near as weak as before. Honestly, this could make a GREAT villain.
I think you're going to be shocked when you take it out of the white room lmao
It's situational. I know that. But that's why it's fun to come up with these really weird build ideas. This one just so happens to be more effective against the players than the enemies they fight, for the most part, part of why I noted it would make a great villain.