To the OP:

A lvl 70 PVP geared rogue is > than 4 lvl 64 shaman unless you catch him in the open at max range, occupied with a mob or in another pvp with no cooldowns avail.

I am not even sure why he bothers stunning your main, he can pretty much 2-3 shot each of your guys if he is geared in S2+

Just level up and get the pvp gear yourself and no rogue will be able to touch you, well they can annoy you, but certainly can not kill you any more.

btw, a lvl 70 mage would own your entire group just as fast if he made into your group and started exploding, those can still be a pain at 70 if you are already hurting.