Why? The other classes that wear both light and medium have far better defensive cool downs. The only time it's benifical to have is when you're taking. Besides that, wearing heavy armor as dps sucks. All the defensive cool downs the other classes get on short timers far out weighs having better armor - espcially when some of the classes have abilities that midgate most of your dmg abilities. I'm a BH and all I get is a shield I can pop ever 2 mins for a cooldown, thats it...
I know tanks will benifit from the heavy armor, but the DPS people need better defensive cool downs to compete with some of these other classes. I'm not saying we should get something op, but something on a shorter timer would be nice.
Here is a list of all the defensive cooldowns a sorc has in an alphabetical order:
Where are these great def cd's you spoke of?
(I know that we get one with 2.0 which in reality is there to take us completely out of combat for it's duration, you could even say it's a selfapplied cc)