Just think about it. A much large scale Wintergrasp/Tol Barad that is open constantly for PvPers to battle it out, siege weapons/vehicles. Towers to capture and defend an ongoing battle through the day rather than every couple of hours like how wintergrasp/tolbarad were.
I think WvW would be an awesome feature for WoW, given the cross realm and cross zone features we have now. I think this can be implemented really well.
I played GW2 til about lvl 17 on my Charr Wariror whilst i waited for MoP to launch but since playing my ret to 90 and then my human monk i cant see me returning to GW any time soon especially with patch 5.2 my monk gets even more fun!
But I did think WvW would be amazing for WoW. Constant battle instead of just queuing for BGs/Arena.
What you guys think would you want this in game? I'll add a poll.