I tend to like certain professions more for certain tasks.
Right now, my favorite profession for WvW is Engineer. That's why she got the full exotic set first :)
Mortar elite is just awesome at raining hellfire from a fortress wall, unlike other ranged weapons, those mortar shells are ballistic so they can go over the edge from a safe distance. Even for grenades I have to go to the edge of the wall, and expose myself to some serious damage and even risk of being pulled over.
Then, the grenade kit is just awesome at ranged AoE, any regular weapon set is good at picking off single foes at a range. Shield is good defensively, or to block people from entering their fort which explains my pistol+shield preference.
And you get a good elixir for running speed, and some turrets for extra damage at a safe distance (they keep firing even if you back away, and many don't shoot the turrets down).
And for a change of pace, you can equip the elixir gun and play a more support / healer role.
Now if I can just figure out good traits.