I dont listen to Heavy Metal/Metal.
But I can definitely respect the shit out of it. And enjoy watching some of the instrumentals. Im more into the Jam Band scene/Funk/Jazz..
And as for Metal guitarist and bassists... They really fit into Jazz for me.
Its like high tempo jazz.. On major amounts of cocaine. Good shit.
I'm not into death metal vocals but agree with the rest of your post. The technical aspect of the musicianship cannot be ignored. This may sound lame but its even more impressive when you see a guy like Chuck playing an intricate guitar piece while singing at the same time. It's tougher than people think.