D/D is amazing at surviving, trolling and controlling, but does shit damage. D/D eles can be extremely annoying and immortal, but I can't even remember the last time one killed my almost full glass cannon mesmer. It also has a much higher skillcap than most other professions.
As people have suggested, D/D ele. I don't know how they perform in PvP from personal experience, as I use a scepter / dagger on my ele for PvP, but in PvE I quite enjoy my D/D ele as having quite a lot of damage in addition to a fair range of support and control abilities.
I wouldn't personally build glass cannon for sPvP. D/D might do a lot of burst damage but if you meet someone with survivability and sustained damage (e.g. greatsword guardian using the invulnerable elite to halt your initial burst and a consecration to remove conditions. You are forced by your range to be close to them, where they can heal, retaliate, cure conditions and do sustained damage), they will probably mop the floor with you.
Fortunately, the only class I ever end up meeting in sPvP is a glass cannon mesmer and providing you can figure out which mesmer is the real mesmer, they won't last very long if you get rid of control effects with an ability such as Armor of Earth.