Well, AotD + Sphere is also a bug, but it can be exploited. Admiral's Hat is the same. Although, if Baratorch fixes it, I don't think anyone will be upset.
Why is AotD + Crown of Sorcery considered a bug? I think that magic from combined artifacts should be perceived as an ability, not as a spell. Crown of Sorcery doesn't suppress the magic of, for example, fairies... or the magic of uniques, and Zandars, etc. Or is that all bugs too?