Scourge Strike can now crit only once. The Shadow portion of the damage cannot separately crit. We wanted to keep the double crit mechanic as a way of making Scourge Strike do more than just being an attack that hits for equal part physical and Shadow damage. The change just proved to be too bursty in PvP and provide too much sustained damage in raids. The Shadow portion Scourge Strike will continue to be increased by effects that currently boost Shadow damage.