Would this have implications for using ANNs on recursive structures (trees and graphs)? Their "position encoding" seems a little contrived, but may be amenable

Would this have implications for using ANNs on recursive structures (trees and graphs)? Their "position encoding" seems a little contrived, but may be amenable to a more complex positioning scheme (e.g. paths from a root node). Whilst there are "standard" approaches in computer vision ("CNNs applied to <foo>") and sequence processing ("LSTM RNNs applied to <foo>"), there doesn't seem to be any "standard" for variable-size, recursively-structured data. Sure there's recursive ANNs, backpropagation-through-structure, etc. but they all seem like one-off inventions, rather than accepted problem-solving tools.