Again your going by todays standards and you are speaking as a fan of metal today. I grew up when AC/DC were considered Metal by all and that includes "metal" fans of yesteryear (yes the maiden,priest,sabbath etc. fans of those times). I have no doubt that if you grew up in the 70's and such you would of thought differently because that was the acceptance/train of thought of metal fans about AC/DC then. And there is no rules saying metal must be complex and cannot/should not do verse/chorus/verse song structures. Alot of the bands you do consider metal have used that structure and some still use it & have never changed. This is not about extreme metal which is the problem when people cannot consider anything metal unless it is extreme metal or influenced extreme metal. A rock influence in metal songs should not be excluded from calling it metal because metal is a versatile genre that takes many influences from many different types of music and makes it unique within the metal genre and that is what AC/DC did and Motorhead took to a further level afterwards.
With the exception of Sabbath, AC/DC were the heaviest band of their time until Motorhead came around in the mid to late 70's. AC/DC were simply pushed out of being considered metal at that point but that doesn't mean they weren't a new metal band for a new genre called metal in the early 70's to begin with. They simply became a mainstream metal band with the release of Highway to Hell and/or Back in Black.
And I would have to agree with Vihris & King Richard that at the very least AC/DC is borderline or in the grey area in this issue.
