Hate to break it to you dude but 5/10 is 50% in and out of school. If a Cd gets a 50% that means its not good enough to be considered better than average. I think Opeth deserves higher ratings.
"Grindcore is characterized by heavily distorted, down-tuned guitars often showing crust punk-influenced riffs, blast beats by drummers, short songs, and a vocal style consisting of growls and higher-pitched vocals", thats the definition of Grindcore. The guitars in Wreath arnt downtuned, they dont have any crust punk influenced riffs, there arnt any blast beats, and the song certainly isnt short. Sure there are distorted guitars and growels, but alot of Opeth songs have distortion and growels. That doesnt make them Grindcore either.