Still don't get why people insist on this. If it was a PvP based game surely they'd have world pvp right? Not talking about WvW. Just because it actually balances the classes correctly doesn't make it a PvP based game.
Since when did open world PvP make a game a PvP game? WoW, SWTOR, Rift all have that and the all primarily PvE games where PvP is a secondary consideration.
There is a quote from onw of Blizz devs that often gets repeated (usually in regard to their utter failure to provide balance in PvP) which bascially goes 'I wish we never introduced arenas, because it is impossobel to balance unless you design the game around them from the start', guess what GW2 is designed aroudn competitive PvP from the start, it is not a poor cousin to PvE.