BTW, the reason your killing a PvP 10 caster is only 2 reasons:
1. Your being allowed to do so because of how OP a lone sin vs. a caster can be. Where is the team, would you be killing that same caster if they were supported? Are you good enough to waste them and get away before the melee show up? Or are you attacking lone casters on a ledge or running back to the group? If so, how long did you waste waiting to pop out of stealth? Why are you alone and not with the group? Why is that caster not with the group? You see sins shine when they make it a 1v1 situation. 10-1 if that caster had even just 1 other person with them on a PvP 2 I doubt it would be so easy. Once several people decide the sin needs to go away, usually it's farm time for that sin.
or...
2. That PvP 10 caster is a full time bori-warrior with little to no real PvP experience and in that case you could be on a PvP 0 in level 70 blues and waste them.
Also, LO is silly, but hardly game breaking when melee wake up and farm out the sin the same way he farms out the caster.
Sin is like demo, a silly class that can do well 1v1 and in groups with support, but once people decide to focus you and stay on you the match just turns into a silly survival challenge, which is much easier for a Sin because of hide