Do Sorc/Sage healers need a Defensive Cooldown?

Currently when being attacked by more than 1 (or 1 good) melee dps a sorc healer can be completely shut down, and without a guard is a free kill for almost any melee dps. Right now, the only time to get heals off is to sprint and los heal with 2 fast Dark Infusions. However, the nerf to the cast speed of Dark Infusion will make this almost impossible.

Playing both a melee dps and a Sorc healer, I can say that even pre sorc nerf that they are the easiest kill of all 3 healers, regardless of their skill (minus huttball). Outside of huttball there isn't much they can do to defend a melee zerg, and it will get even worse next patch.

What does everyone think? Do sorcs/sages need a defensive cool down like the other 2 healers? Will they be able to compete with the other 2 healers next patch?