You get into this kind of metal because you think that it's all the good things about "rock" music, without all the moron parts and then you get into classical through metal. Finally, you see the classical music is much better than metal, even though the metal is very good, and you only just then realize what "heavy" means.
To me, they're complementary. Take Kraftwerk, Burzum, Deicide and Brahms, Bruckner, Schubert: they each have a place. I cannot subtract any from my life because they are all relevant. Burzum I listen to when I have time to focus and appreciate, much like Bruckner and Brahms. Schubert and Deicide are more portable, as is Kraftwerk, but I find myself returning to them in solitary moods as well. They are all visions of the same continuous idea.
I believe metalheads will learn to integrate classical and some keyboard bands when they see this continuity. The furthest-ahead of them already do. It is a sensible way to expand one's mind and find more to enjoy, and shows transcendence of category ("metal","classical","ambient") in favor of what we might call artistic genre
, or vein of thought, such as "Romantic music" or "transcendentalist music" or even simply the philosophies themselves, "art in an idealist, transcendentalist, holistic realist sense"