Whether you like their Thor stories or not, they have earned "master" status and fan respect from the totality of their body of work in comics.
Personally, I hated World Engine, but I do not judge Warren Ellis by his Thor run alone.
Frank Miller, despite his more recent runs, is one of the best comic book writers in the modern era because of his phenomenal Daredevil run , Elektra , Year One and Dark Knight Returns.
If you're going to lump them in with Stan, Jack and Walt then those three should be Grand Poobas or something beyond Master.
But in the era where everything is EPIC, I suppose you're right. Mediocrity should stand hunchback to shoulder with the best. It's only fair. Wouldn't want to hurt anyone's feelings. I'm surprised you dislike Aaron's work so much. Seems right up your alley.