I didn't do vanilla PVP so I don't know But I do know that BC, WotLK, Cata, MoP and WoD were rewarding to do PVP for many reasons. Trade in honor for crafting mats, gems, jewels, transmog, vendor items for gold, etc. Do the PVP daily that used to reward gold for a BG win or the dailies that rewarded bonus honor and conquest points. Wintergrasp, Tol Borad, etc.