Are Witches weak? Ahahaha, you made me laugh.
Slow (Advanced Magic level) - a death sentence for high-initiative units.
Punishing Strike (Advanced Magic level) = +9 attack to any stack. A devastating ability.
Dispersion (no level required) = 50% damage reduction for ranged attackers.
Disrupting Ray (Advanced Magic level) = weakens the armor of tanks.
And after all that, Witches are weak? That's funny...