Cooper's later 80s stuff is more hair metal, not a good way to get metal people in (although I agree that it has some really kickass stuff). Dragontown is an even worse intro imo; it's "heavy" in that it has loud production and chuggy riffs, but if it wasn't Alice Cooper fronting it, there'd be no reason for a person actually into metal to listen to it.
imo the classic early 70s stuff is the best entry point, especially an album like Killer which has some relatively heavy/riffy moments but not in a way trying to be metal since obviously metal wasn't a very big thing back then.