Not to get ahead of myself here before her changes are even on the test server, but as far as i can tell while these changes are nice they quite simply will not make her good or at the place she needs to be.
Her ultimate takes way too long to set up for the amount of damage it does, which quite frankly, even with 3 spheres is at most a couple hundred more damage than say an ultimate like Final Spark that is not only aoe, has a shorter cooldown, has a massive range and doesnt take a huge amount of time to set up.
You either need to reduce the cooldown on Dark Sphere, make orbs last longer, or something else to make it easier to get the full damage out of her ultimate.