I would honestly argue that Q is the more damaging change here as he already has mana problems to begin with and now his main tool for csing, poking, and damage in trades will cost more, and given that Q only gets useful for trading when maxing it and this change quickly destroys him.
To me these changes seem like a straight up champion gutting until a rework like they did with old eve, something they promised they would not do again because no champion deserves to be so completely unplayable that players report you for even picking it.
edit: i almost forgot they are also massively increasing the power of lifesteal and armor pen as well, items maokai must rush to be effective, and now if he does so he loses out on the majority of that armor gold the moment someone buys a buffed armor pen item on lucian, or anyone else who can abuse the changes.