Part of the complications with balancing refreshed classes is that they're competing with subclassed combinations that have more specialization than the design goals. And I can see how outright nerfs to things like Fatecarver would also hurt pureclassed Arcanist builds too - and they aren't the problem, are they? But Herald of the Tome isn't so strong just because it's full of high damage active skills. It has those AND crit damage AND penetration AND weapon/spell damage AND status damage. So, why not swap around some of the most egregious passives with passives in other Arcanist lines? It would be simple, wouldn't affect pureclassed Arcanists at all, and would be part of the overall plan anyway. Surely, that would be easier than doing targetted temporary buffs that make actually balancing the refreshec classes impossible until those are removed anyway.