But really though at the moment I try not to see black metal in a spiritual way at all because for a lot of the more fierce and violent side of the genre (including the hardcore influenced stuff) it doesn't come across like that at all. The primitivity can be appealing (old Absurd >>>>>>>>>>> later Absurd) but I don't really see it in a philosophical context.

Sorgsvart might appeal to you - they're an anarchist symphonic-ish BM band which sounds more like Nokturnal Mortum than WITTR

late 90s NM at least

Falls of Rauros and Oakhelm probably also fit the bill though I'm not a huge fan of either TBH. Some other stuff here: http://r-a-b-m.blogspot.co.uk/search/label/pagan%20metal though I can't vouch for the quality of much of it. I should point out that much of the cascadian BM scene (Skagos, Fell Voices, Lake of Blood etc) probably have similar beliefs to Panopticon (if less overt with the norse pagan stuff).

Holy shit, you did document (a good portion of) Arseterror's discography. I wonder if his Universal Challenger side project is still going, that one did occasionally produce some good stuff.