The PvP Rank system in Classic has nothing in common with the one in the Retail version. Each Rank is a new challenge but the rewards are worth it because sometimes PvP gear is the best available option.
Rank 1 will grant you with Private/Scout Title and a PvP Tabard
Rank 2 will grant you with Corporal/Grunt Title and PvP Trinkets
Rank 3 will grant you with Sergeant Title and a rare PvP Cloak
Rank 4 will grant you with Master Sergeant/Senior Sergeant Title and a rare PvP Necklace
Rank 5 will grant you with Sergeant Major/First Sergeant Title and rare PvP Bracers
Rank 6 will grant you with Knight/Stone Guard Title and the access to the officer's barracks
Rank 7 will grant you with Knight-Lieutenant/Blood Guard Title and a rare PvP set of boots & gloves
Rank 8 will grant you with Knight-Captain/Legionnaire Title and a rare PvP set of chest & legs
Rank 9 will grant you with Knight-Champion/Centurion Title and a PvP Battle Standard
Rank 10 will grant you with Lieutenant Commander/Champion Title and a rare PvP set of helm & shoulder
Rank 11 will grant you with Commander/Lieutenant General Title and the access to PvP Epic mounts
Rank 12 will grant you with Marshal/General Title and an epic PvP set of gloves, legs & boots
Rank 13 will grant you with Field Marshal/Warlord Title and an epic PvP set of helm, chest & shoulders
Rank 14 will grant you with Grand Marshal/High Warlord Title and an epic PvP weapon
Active Game time
lvl 60 character