WoW tends to be great for 'average' systems but as the years go by the new standard for average goes up.
Anything i5, 4GB RAM, and dedicated graphics can handle WoW well - what I run is great but I'd love to have excellent (aka running everything in High/Ultra without low framerate ;0;)
Diablo III North America Glacea#1307
League of Legends Queen Nimera, Level 20
New Leaf/Pokemon XY 4511 - 0825 - 1589