> ALSO this has meant for me that when I need to move or re-use a component from one part of the hieararchy to another, I often end up needing to completely rew

> ALSO this has meant for me that when I need to move or re-use a component from one part of the hieararchy to another, I often end up needing to completely rework the props of a BUNCH of other components, so the right prop can be passed down to my now-moved component -- that's what I mean by 'requiring cascading changes'. This sounds like the problem that is solved by redux et al. Instead of passing props into a component just so that it can pass those props down to its children, the child components can just connect to redux and get the data. That way you are accessing the data at the point in the component hierarchy where it makes sense for the component to know about that data, instead of in whatever component happens to be the common ancestor of all of the places that need the data.