Is it? I really saw SoW for only 3 purposes:
1. Speeds up mono aether with huge attack boosts (is it really necessary with psion and recluse?)
2. Be able to buff up your immortal creatures like golems (needs an extra card as a combo, but this is half defensive, half offensive)
3. Be used to reflect opponent's stuff (is a pure defense variant, sort of like liquid antimatter)
But if you wanna get down to it, shield bypass is probably worth +2 in cost. +4atk along with spell damage should probably have this at around 6
. Really depends on how much you feel the "mandatory quint" counts as a penalty (in this case, around 5
).