Just something that was in DAOC that was really fun and gave us all a lot of incentive to go to WvW but say whoever owns the center keep of the eternal battlegrounds gets to unlock a special open dungeon for everyone on that server. Kind of like DF in DAoC.
The dungeon would be huge, almost like another zone but it would be filled with monsters that require large amounts of people or just small groups. With this you could add a whole new token system and cosmetic rewards for killing the monsters within this dungeon.
Just a thought