Hickman points out that they wanted the game to include a full battery of social features, including open groups, public quests, and other grouping tools, but they failed to design the game itself to encourage grouping. Part of this lies in the player versus environment quests where the gameplay was too easy and players didn't have a reason to group up.
The economy of WAR also suffers from this problem, as the economy is too loose. The economy doesn't offer players enough incentive to work inside of it, leading to players forsaking the issue entirely and working on their own.
If you're looking for more of Jeff Hickman's thoughts and plans to help change the tide of WAR, check out the full speech notes over at Gamasutra.