I don't know. I wouldn't describe Teitanblood as being anything near Incantation or Demoncy. Their primary approach is something like a very dirty thrash/speed metal style (maybe Morbid, early Mayhem and South American bands) mixed with something like Inquisition-type black metal or Blasphemy as mentioned. Most of their output did not impress, but something about Seven Chalices had a very Necros Cristos feel to it that clicked well with me.
Otherwise, I agree with the rest of OP's observations. Having enjoyed Goat Molestör's work, I was looking forward to Grave Miasma's EP when it turned out to not be very impressive. It was just too linear and predictable to be highly enjoyable, much like the rest of these kind of bands. I'm also on the lookout for newer bands to impress me, but it's hard to come by. A few that come to mind are Demoniacal Possession, Cruciamentum, and Embalmed Souls. Also Kerasphorus, but there is a thread here somewhere about that already.