Gaile Gray commented in a forum thread that ArenaNet has no intentions to add an offical DPS meter to Guild Wars 2.
The full quote:
Hey guys,
We have a lot of tools that we use in the development of the game, but not all of them are available or supportable in the live game. Adding tools to the game that would require continual updating and maintenance would not be the best focus for the team. So while we’re aware that some players would like to see an official DPS meter — and clearly the community is divided on this topic — you should be aware that the team does not intend to add one to the game.
From:
GW2 News Blog 