I can't understand why they are buffing her ult. Her ult is already strong. Her weaknesses are wave clear, really high mana costs, too long cooldowns and no mobility. Having no mobility is normal for a burst mage but I think the real problem is her other weaknesses. For 'too long cooldowns' I don't mean her ult. Her basic abilites need less cooldowns. Maybe remove the ult cooldown refund and reduce her other cooldowns slightly.
Q: 13 / 12.5 / 12 / 11.5 / 11 => 12 / 11.5 / 11 / 10.5 / 10
W: 14 / 13 / 12 / 11 / 10 => 13 / 12 / 11 / 10 / 9
E: 10 => 10 / 9.5 / 9 / 8.5 / 8