I think you're misinterpreting what anus.com guy says (his usual claims of neo-classical intricacy or whatever in a random death metal band) for actual, intentful following of classical mode of composition and studied tradition. There's actual cases like Gorguts, where Luc has composed serialist compositions for small orchestras and whatnot as part of going to school for music, but it's a very small part of the scene.
Not really. Possessed, Kreator and Slayer are all on the record as saying that Bach was a major influence (and it's obvious to anyone who knows what they're listening for). It's never been a question of directly imitating any particular classical style. Nor is it necessarily a matter of consciously being influenced by classical composers (though, in the case of most of the better bands, composers like Bach, Beethoven and Wagner are definite touchstones, and are generally cited as influences).
There are three areas in which the classical element shows most obviously in most of the better metal bands. The first is tonality. Metal tends to be modal, diatonic or chromatic, like classical music, and is rarely written in the pentatonic scale so typical of rock music.
Most of the better metal bands are much closer structurally to classical music than to rock. This is true at both a mechanical and conceptual level. In rock, instrumental music functions largely to provide rhythmic emphasis and harmonic shading to the dominant (vocal) melody line). In metal, as in classical music, the melodic element is carried within the instrumentation, and the vocals either provide a doubling of the dominant melody, a secondary melody, or (in extreme metal), an additional percussive element. Metal also makes use of many techniques found in the classical tradition, but not within rock music, most notably modalism, polyphony and counterpoint.
On a macro-structural scale, most metal post-Slayer (and Mercyful Fate as well) has been built around linear, narrative styles of arrangement reminiscent of classical music, but not of the stripped down verse-chorus arrangements that are the bread and butter of rock music. Even when metal makes use of a verse-chorus format, it typically does so in a heavily modified form that still internally reflects the classical influence.
Rock music and other pop forms are heavily circumscribed in their range of expression. The basic structural forms and limited array of tonal techniques mean that rock bands deal mostly in broad gestures - a single mood or idea explored without variation. Metal, like classical and ambient music, tends towards a form of artistic structuralism, with meaning signified not by a direct one-to-one correspondence between lyrical and musical content (as in rock and pop), but by the placement of lyrical and musical elements within the larger structure of the song.
It goes without saying that the warrior ethos and Will-to-Power elements that form the heart of metal's conceptual framework echoes the heroic and epic strains of the classical tradition, rather than the party hearty hedonism of rock (which isn't to say that metalheads don't party, just that metal subordinates hedonism to and sublimates it within warrior idealism). Bottom line: there's no way to honestly talk about metal without placing it in a neoclassical context.