I guess someone will have to do the math to find out if Shadowflare is even worth the gcd. Bane is an ogcd, and you still have two DoTs, so I still see no reason to not cast it, but Shadowflare is questionable.

As for Broil II being AoE, I am not quite sure how Ruin Mastery works. Ruin2 is instant, but Rune and Broil are hard casted. If Broil 2 is separate from Ruin Mastery then I see no reason why it couldn't be AoE. SCH needs something. A ways back, I brought up an ability for SCH called 'Aetherial Implosion', which when used, causes Shadowflare to implode causing damage to all enemies within with a potency that increases the longer Shadowflare is active. As with all my ideas, it was shut down, but it's funny how they took a similar concept and gave it to AST in the form of Earthly Star.

We will have to just wait and see how SCH gameplay turns out in 4.0, but it will likely need some tuning after SB is released.