+1 for WoD being prime world PVP. I remember spending hours chasing down damned Predatoria as he was kitty ganking people with his posse. Then the tugs of war in Shadowmoon Valley between Outpost for hours and hours was HUGE fun.
Lastly, I remember stopping select Horde toons from bidding on my BMAH boxes using alliance alts lmaooooo by pvping in Nagrand.
Again, that was much more fun to me than any MoP world pvp on walls by pvp vendors in Townlong Steppes or running in and out of safe zones in Vale.
MoP had Timeless Isle, which was probably my fav part of the expansion being able to Censer of Eternal Agony and get delcious Bloody Coins muwahaha. Also, the Falling Flame was boss for wpvp and I literally had charges on it until BFA (gluck trying to farm it lol).