Whenever you are kiting an opponent with heat to spare, If you have already used your knockback, stun and concussion stun, then you should be using your rapid shot slow until you get distance between your opponent.
One class I had problems with were marauders when I was arsenal specced. Now I just kite them until they leap me, then I knockback, when they close the distance a second time, I stun. By then they would be dead.