Do not play thief, anet hates this class with a passion and so does the population; no one wants a thief in pvp nor in pve so please remove this class from all lists. Heck, should just remove thief all together and be done with it finally.
But they are great in Arah and in TA
Anyway Tempest are great, not just at bursting, a staff tempest (the squish-iest build) is very good at CC, heals and damage. As for things that move around, we have air overload. As for things that stand there we have fire overload, for support we have water overload and the tempest heal skill. And we have auras, which in my opinion is abit meh, cos we have Elementals, and we have Glyphs.
And against those irritating snipers we have projectile reflect. We embrace diversity. EMBRACE THE ELEMENTS. But we seriously need more defense. Like alot more.