ok...Dread I need you to be even more specific if you can. I need to know what your criteria for something to be considered metal is.
What is it that makes Deep Purple, Zep, Sabbath or BOC metal.

you said, grinding riffs, doomsday whistle etc....

I think if you listen to some dark norwegian black metal, or some drone, you definately feel a sense of impending doom. In fact, with the tuned down guitars, I dare say that it makes the above mentioned bands sound weak in comparison. It's certainly not my cup of tea, but I can't deny that it's terrifying.

To me, art is truly subjective. While I may not "get it." It doesn't make it any less valid.
I liken it to those trad kilt wearers who say that UK's or AK's aren't kilts. They are decended from trad kilts, but it doesn't make them any less a kilt.
they still have the characterisitcs that define the word kilt.

So if metal is meant to be loud, agressive, bombastist......then I think today's metal is no less metal than that of yester year.