its because the bands of today (stained slipknot static-x and all the others) dont have the same tonal reach of the 80's stuff. most of the newer bands start off heavey but when they get to a verse they either slow down or growl into the mic. alot of the older stuff a singer actually sang (for instance motle crew queensryche iron maiden) and the virtuosity of the guitar playing gave an opening to not only ultrafast playing but solos and lead work that bordered on genious. but thats just my view.