Originally Posted by
Valech
What implies that it roots us? The word "defensive posture"? Whenever Blizzard implements something, that has possible negative impact on your performance, they try to balance it with something else. Taking more damage as Fury? here, have a frequent self heal and a higher healthpool. Now, if these balances are sufficient is another topic, but since I do not see the ability of shadowflame shield outweighing a possible root in any kind, I highly doubt that it roots us.
Another topic is, that I beliebe Black dragon´s always used shadow as their element. Nefarian being a great example, as the eldest son of Neltharion. We even had to wear a damn cloak to shield us from his Shadow flames.
I am not sure how right I am regarding Lore, but I always associated (cleansening) fire with the red dragon swarm, nature magic with the greens, arcane with the blues and shadow with the black swarm. Just like shadow priests use shadow attacks without being corrupted.