For me the only important thing to establish is that magic is Impersonal, Unintelligent, and Natural.
Impersonal: There's something I hate about magic when it operates according to the worldview of people. I'd rather have it work its own way and people have to figure out it, they way they have to approach science.
Unintelligent: I don't like there being an intelligent force behind or controlling magic. This applies both to gods and the "minds/souls" of people, and even to the idea that magic understands "words". Magic should be a natural force, and like all natural forces it doesn't have an intelligence. There is no Will inherent in the universe, no ultimate cosmic element that has any kind of mind whatsoever.
Natural: None of this "magic is separate/comes from another dimension" stuff. Or the "magic is unnatural" stuff.
Beyond that how you get it to work isn't important.