(1) Ambient metal in the Darkthrone Transilvanian Hunger
/Immortal Pure Holocaust
style: break up the drum phrases, emphasize bass drum over snare, make it more like a pulse than a "beat" and thus de-emphasize the verse/chorus distinction.
(2) More like Summoning Dol Guldur
except more variety in melody and perhaps even less of the traditional black metal and more of a new genre that doesn't fall into pop/folk imitation like Let Mortal Heroes...
(3) Not metal, but why didn't Vaesen make more albums like their first? It's godly. The rest try too hard to be rock music, which they aren't.
(4) Deeds of Flesh Path of the Weakening
-- what made this great was its inclusion of melody and seemingly random song structures that still came together. They never quite hit that point again. Why no one else?
(5) Who inherits from Suffocation? Pierced From Within
was brilliant but reined it in from the second album, which really had a lot of undeveloped potential.
(6) Phrasal death metal. Early Massacra, early Incantation, and Morbid Angel Covenant
showed us the power of this kind of riffing. How did it just about entirely die out?
(7) Ancient Trolltaar
showed metal how to build longer pieces that were not entirely dark, but had varied moods like an opera or theatre production.
Why haven't metal bands gone ancient Greek (no, not that
way) by incorporating drama, poetry and music together into one artform?
I won't ask varieties of "the sell-out question," such as why Trey and Dave are dicking around with an artform that will never reveal their talent, instead of making complex death metal, or why Gorguts has a hardon for deathcore.