it looks quite good and the colors work to make the thematic grouping easier to understand, still I think it would be even more understandable if the same tagging (as node and area) would have the boxes directly adjacent (e.g. railway=station mapped as node and way is on opposite sides of the diagram, would better be close to each other).
The idea to have 2 diagrams, a “mapped-as-node” and “mapped-as-polygon” version, also sounds interesting to me, although I think it isn’t obligatory and could be understood with everything in a single diagram as well.