OK Mathias, I finally gave that Nazgul album a listen last night. I was quite impressed. The vocals were a huge put-off in the beginning but as time went on they seemed further down in the mix, until they felt like they were at a tolerable level. As for the actual music, it was amazing. Rich orchestration and competent riffing. I really wish I owned a copy so I could read all the Latin lyrics.
One criticism for this album is that the songs are too short for the kind of music they write. Complex orchestral black metal, like Obsidian Gate for example, requires long songs to achieve their effect. Most of the Nazgul songs seem to end abruptly, like only half of the journey through each song was completed. Better songwriting would truly benefit this band. More songs like "Solvitur Ad Elfmuth", clocking in at 8:44, would have been the way to go.
Still, an album full of beautiful songs. But they should have lengthened them and cut out the pretty interludes.