I like homebrew also. I really do. But don't call a creature a spectator if it acts like some sort of beholder that can also unpetrify people. Give it a new name and unique backstory. Don't call it an intellect devourer and have it act like some weak brain dog.
A spectator is a young beholder. It is normal for some creatures to be stronger/more developed than their peers. He has got a trick or two from daddy/ mammy. And it does prepare you for when you meet a real beholder.
Well, I do think that Us has the newborn tag and has the same stats as the intellect devourers you fight. You might assume they have been breeding new ones (there does also seem to be some kind of a "plague" on the nautiloid that was killing mindflayers).
Personally, the most useless nerf they have put was to remove the resistances on the imps and the young hellboars. I think it is a great lesson on the tutorial to learn about the resistances of some creatures. But it is a minor thing, at least for me.
