Another point: I would raise her attack speed to 1.67 per s (Valla/Illidan) and decrease her basic dmg to 30 (Illidan). Otherwise, you can not make really much use of your trait and I assume she would become a one-hitter with all the dmg boosts your build contains. Not proof, would have to be tested^^ Btw, would be closer to the original's attack speed. 1,20 feels really slow. Even slower than unbuffed Tyrande or Kerrigan (both 1.25).

Really like your concept, sounds very interesting to play^^ For her as a mage slayer I would maybe add Spell Shield on Lvl 13. Or maybe make your own Spell Shield out of Fade (has to be activated) and add the CC reduction to Burst of Speed. Burst of Speed btw would be nicer if it would trigger on activation, too (can be activated even if stunned). 60s CD is enough, I don't think the talent would get OP. Fade could grant invisiblity for 3 seconds and invulnerablity to the first ability...

- Substituted the ability Ice Armor for Mana Shield to get closer to the original Lady Vashj from WC3. Added some new talents referring to it. - Simplified both AA-specifying talents at Lvl 7.

Appears a fun concept overall, but 1 question: What exactly do you intend with your first ult "No Escape Even in Death"? If I got it right, Kel Thuzad is channeling, so dealing no damage on his own, while he controls an enemy hero that is weaker than usual. Furthermore, he is left completely exposed to enemy heroes and the ability can be interrupted with stun. It appears a rather bad deal to me and by no means worth the 150 mana it consumes. Is it just me thinking way too...

Added some talents, others to come in future. As so a more colourful structure^^

Feel free to post ideas making her suitable to your favored playstyle but not OP. Concept is still lacking in talents. But: I do not think she should get movement buffs or teleport. She still has her "mount" and with all her CC she should not feel the need of buffing her mobility any further. Not even should she rely on her "mount"; trough her sidestepping during the animation the chance of being blocked by structures should be rather high. Let me know wether you think...