I very well may be wrong but isnt engineering the tree most pvp snipers use b/c all the abilities that allow them to hold caps and such
The main thing about engineering is AoE and survivability. You'd wonder what makes engineering so resilient, it's the Tier 6 skill, deployed shields which basically transforms you into a heavy armor class when you take cover. The other thing is more powerful shield probe. I still have no idea how much damage that thing can abbsorv but it's huge with engineering. And since you have EMP Detonate, you can get a second one shield probe when the first one ends.
In combination with ballistic dampers and entrench, this allows for some pretty good burst damage mitigation.