Not sure if there's a better thread but recently I compared again MM6 soundtrack to those in 7 through 9 and I wondered, does anyone know why it gets so much worse?
6 has pretty elaborate and with a wide range, peaceful, scary, threatening, or with a booming monks chorus. And most importantly, a lot of ambient sounds are actually baked into it, like chirping birds in Ironfist, howling winds in maps such as frozen highlands, and dripping water in many dungeons.
Parts after that just have some weird new age meditation music with no effects. Day of Destroyer is probably the worst, just try the track that plays for dragon cave and murmur woods.
However the composers seem to have been mainly the same for the games 6 - 9 and I can't understand the perceived stylistic change after 6.