I want to thank you for doing this -- it got me to re-read Macbeth again for the first time in many years. I didn't re-read it before making my comments, since I wanted to be as close as possible to unfamiliar with the story, and I may have been a little too close. I had forgotten the Norwegian army was involved at all, and assumed they'd be helping out Duncan and not the rebels (so that's one comment you can strike off!).
Macbeth is so entertaining on a soap opera level -- in fact, I think between it and Midsummer Nights Dream all the tropes are covered, if you allow abduction by fairies to substitute for abduction by aliens.