^sayin, kevin knows what's up.
also if you really want to go into the phenomenon. Nu-metal was a direct result of kids growing up just like I did, the suburbs were flooded with both hip hop and metal/hardcore/punk, it was all inclusive.
I would play hoops on the weekend in 7th grade, my friend and I would bring Metallica and Megadeth and the Hispanic and Filipino kids would bring The Chronic and that 1999 Bone Thugs album and we would listen to those four cassettes all day, kerry king chillin with the beasties, aerosmith and run dmc, etc, living colour, fishbone, bad brains, etc etc....nothing was segregated anymore.
A fusion was bound to happen.
Unfortunately, all those bands managed to completely suck at both rapping and playing metal but, that's just the way it went down. For every Candiria there were 1,000 Hed PE's and Crazy Town's, thems the breaks.
Even though Roots is a great album, it did bring about the trend of bands thinking "woah, they just tuned down their guitars and played some jumpy riffs on one string" and everyone started playing like that, but I think that Roots album crushes and most everything trying to copy that style (even soulfly) fails.
but for sure, Roots would be to blame more than Pantera any day. Pantera was the epitome of metal at that time, especially in a more mainstream context, they were brutal and experimental compared to the shit metallica and megadeth were doing then.