Not trying to give you a hard time here but just want to point out my feelings on this.
1) loud and/or fast drums beats is not soley the property of metal, (more a common problem with drummers LOL). Nor does metal HAVE to have fast drum beats or "blast" beats like you mentioned earlier. Sabbath was the king of sludge and had many slow steady grooves. Maiden wasnt always balls to the wall either. Many metal bands have had slower paced steady grooves
2)Dickinson and especially Ozzy were not that overwhelmingly aggressive. There were previous(Dickinson) and concurrent(Ozzy) hardrock vocalists more aggressive and raspy. Many early metal vocals were clean as could be and many today still are.
3)up front guitar has been a mostly standard policy of rock, the heavy stuff started with hardrock. Minor keys I dont get, it all converts to major to me, but Maiden used very basic common progressions and stood apart from hardrock in their constant usage of pedals and gallops, something actually started by hardrock bands such as Uriah Heep, Zeppelin, Heart, ect. One thing early metal guitar players did do was steered further away from pentatonic improv and I/IV/V progressions but again hardrock, progressive and fusion players did this first. The key word you used here was HEAVY, the crushing weight of the whole thing IS where heavy metal came from. The metal word also refering to the grateing of it, massive over driven distortion, thick grinding saturation.
4)dark lyrical themes, not always existant in all metal and also exist in other forms of music. I think skull and goat fucking however is specific to SOME metal... LOL I mean country folk do it too but dont sing about it, just that the wife left but not the reason why.