No one ever went to a Led Zeppelin concert expecting the band to open with “The Rain Song.”
It’s a fine tune, to be sure, but the electric charge of a crowd in waiting must be met in kind.
The same applies to the album: Kiss didn’t open Destroyer with “Beth,” for example. And Metallica had the prudence to place “Fade to Black” a good four songs into Ride the Lightning.
Read the countdown and see where Pantera fits in here: http://www.guitarworld.com/top-ten-heavy-metal-album-openers