Reborn and Epidemic have always stood out negatively to me. You've got Angel of Death, Piece by Piece, Necrophobic, Altar of Sacrifice, Jesus Saves, and Criminally Insane...and then Reborn. Not dissing it, it's a good song, but that and Epidemic definitely ruined the streak.
I need to listen to Reign in Blood without those two songs and see if the whole thing feels weird. I don't want to call them filler because I think they contribute to the album as a whole and removing those two songs from the album would damage the integrity of it. But I may be wrong.