Look up xpadder it will allow you to use you controller with any game. That's how I play and it works great but tricky getting a good control scheme setup. You can make a shift to double the buttons and you can toggle right mouse button to lock camera, pretty great.
I dont believe there is built in controller support at the moment, would be kind of nice though as ive played some MMOs with one int he past and I think GW2 style would work with it. But even without built in controller support theres a bunch of programs out there that will let you configure your crontroller so that you can use it in any game even without in-game support.
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no official support by Arena Net ( only rumor ) but with xpadder GW2 is really more ... AWSOME
check that http://www.youtube.com/watch?v=DkQRfQ1kwfI