Answer: 20% damage reduction!
I find myself fairly active in Warzones when it comes to objectives, and this means I will probably die a lot.
Fill my resolve bar in Huttball and watch out because I am probably going to pop every cooldown and carry for as long as I can hoping for a friendly to hand off to. I am going to get in your face with DoTs and AoE to keep you from capping my point on Alderaan, or bombing my door on Voidstar. All of this means I am probably going to die a lot.
If you are QQ'ing about a Sorc/Sage who you couldn't kill because they popped a cooldown, then bubbled, and force sped away, then you are bad. You should realize that said Sorc/Sage is no longer helping their team (which I HOPE is your goal).
If you want to cry about the survivability/utility of a Sorc in a purely combat situation then you should sit tight and wait until some sort of arena is introduced. All we have now is instanced, objective-based PVP.
Sorc/Sage is the easiest class to kill OR scare off. Both should be acceptable options. But if you want to chase me all around the map while my other 7 teammates are scoring and capping, go ahead...