Procedural workflow has and is growing and becoming a large driving force in content creation. Something I always knew would be make things very quick to iterate or change, and also keep things consistent and simple, would be referenced colors. So maybe your documents has a palette with named slots, and when you go to select a fill/stroke color, you can optionally select one of these named slots. Other fills or strokes can reference this same slot. Then if you decide you want to change colors later, you simple adjust this palette and every object using those slots gets updated. To extend this concept, it could almost be like symbols but for object appearance where you can have synchronized styles, that way all the parameters are shared, like stroke width, profile, etc.