I much prefer the system in 3rd than the later editions.
The later feel more like a mini game and take away from core of what I like about WFB, which is masses of troops slogging across the field and getting stuck in.
However, I do like the fact that the magic from 4th onward seems to have better flavour.
To me each race and indeed cultures within the same race would manipulate the winds of magic differently.
We see that in the fiction.
Why would a Skaven cast a fireball, that seems too human, why not cast something in keeping with the Horned Rat.
I am keen to see what TOW offers in terms of magic, I hope it is a way to influence the battle rather than dominate it, and that wizards are supplements to the army, rather than wizards doing a lot of the heavy lifting and being key.
I guess I like it when an army without a wizard is at no significant disadvantage to an army with one.