So, another change we see in Wanda: Book-0-Wanda loves trying out all the kinds of magic. She uses hatomancy just for kicks, buffs spells with Rhyme-o-mancy, all in all pretty good. But Book-1-Wanda, is pretty well opposed to the idea. And in Book-2 Wanda just seems to do nothing with her juice. I suppose she might be making items or something with the spare juice, but for all the things she could do, and simply avoiding it? In fact, has she even tried to learn healomancy? Especially when they need it so badly?
Therefore I think that something bad must happen to scare her off from using the other magicks.
Also note about the hat golems: If its just the item off-turn they can be de-hatted. No hat, no unit, no upkeep. Then as soon as you need them they can all hat up and boom! Insta-army.