Lykathea Aflame and Gorguts offer a great example of the difference between coherent and incoherent music. Obscura's phrases are shaped by their position in a given song's narrative, and they evolve into each other in a way that is essentially seamless. The end result is music that is aesthetically and conceptually coherent.
This is beautiful writing but does not contain one actual reference to music.
Gorguts and Demilich actually do pretty well with development. Demilich especially, they tend to actually develop riffs melodically and rhythmically occaisionally instead of just scrapping them and moving on. Dave Mustaine was a master at this, listen to Holy Wars, or Black Friday... Anyway I can't fault either of these bands with what you guys have termed "coherence", but that doesn't make them beyond criticism. Both are HIGHLY stylized forms of death metal, and for most listeners who aren't huge fans of the style the lack of dynamics makes it very difficult to sit through an entire album. How many times can demilich rewrite the same breakdown riff? How far can they go with a vocalist with no dynamic range? How many riffs can you write with the same few tonal ideas? Same with Gorguts, awesome ideas on that album, but it frequently boils down to that same idea/chord pattern being expressed over and over and over again. Their grip on harmony is shaky at best so all the whole moving diminished/augmented sounding chords up and down in parallel motion just gets tiring after awhile, especially when there's very little changes in dynamics or texture (other than what.. a violin solo?) Look both Obscura are Nespithe are great albums for people into that style, but surely not without their warts.
Yes, Opeth has some songwriting deficiencies. Compare Damnation to any band it was trying to emulate and Opeth comes up really short. But when they get cooking, Opeth have great use of dynamics to keep a listener engaged throughout the album, even if the parts don't always blend together perfectly. Plenty of rhythmic variance, lots of nice different harmonic ideas, very good understanding of vocal lines and harmonies for a metal band. They're not _that_ incoherent. Opeth will usually modulate keys using the appropriate harmonic framework, and time sig changes are usually somehow related.
Someone mentioned Burzum as coherent? Well... it's not hard to be coherent when you fucking stretch one horribly voiced chord progression out over a 15 minute song. Moving on...
Atheist, yes, that was in fact a very fucking well put together band... The new Emperor? I mean it was completely over the top, but musically (harmonically, rhythmically, melodically) most of the parts had some reason for being where they were, in fact I remember ihsahn actually surprised me for an extreme metal musician with how generally accurate the harmony in his transitions were. I mean they were probably stolen from early classical composers, but still...
Look, if you need your musical parts developed properly, grab a megadeth, gorguts or demilich disc, if you need dynamics grab some opeth, or new emperor, and if you want to hear what None So Vile would sound like played by an all-homosexual cryptopsy cover band, then grab that Lykathea Aflame disc.
Before you become a snob about your music, go learn some theory and music history. Then come back and torment the crew here all you like, maybe I'll even join in. Until then the phrases of your narrative are just not evolving into something that is aesthetically coherent... man!
D.