iserith
Magic Wordsmith
Also high, but not as extreme.
But all the perception stuff is only an example.
Sometimes, as a GM, I want to craft a particular scene. Setup is important, after which character decisions take the stage and they can resolve/derail the situation as they desire.
But I may have to have spells work a certain way, or in a certain combination, or give a character a way to cast two spells in a turn, or have multiple character types present if I want things to happen a certain way.
I like to give my players the opportunity to be surprised, "How did they do that?" and it would be better for that to happen within the rules, IMO. That way, the players might even be eligible to pursue a path to those abilities as well.
I don't always like the explanation of GM fiat or monster ability.
Since the DM's role to describe the environment, it seems to me that you can set things up as you will. It's not clear to me what issue you're having. Do you have any examples?