Fallujah is a very technically proficient band, like Zack Ohren said, and they wanted the sound to be "huge" not necessarily extremely dynamic. I agree that dynamics would help accentuate the things you mentioned, but I don't think they're going for that.
When I said that everyone isn't Colin Marston, I meant that not everyone wants to make the albums he makes or can. Most metal heads don't care about dynamics or well thought out mixing. They just want to lay some crushing riffs down and listen to it on their crappy stereo. I've known many small metal bands and the last thing on their to-do list is making an epic and dynamic album. They mostly just want to destroy things. I'm not saying we should be complacent with bad production, I'm saying that most people don't have the same goals for their music that you do.
Mostly old death metal lacks coherence and brutality. The mixes were very polite to me. They're dynamic, but not very brutal. Human Waste, Scream Bloody Gore, stuff like that. In more modern music, there's a lot of shoegaze and blackened metal that people are trying to make very dynamic, but ends up just sounding like ****. Another example is Opeth, who I really love. I tend to like their less dynamic albums a lot more than the more dynamic ones. I'll take Blackwater Park over Morningrise any day.
