@ericmjl That’s a really interesting thought. We have considered the same with Edward / BayesFlow. Essentially both of those packages are aimed at researchers giving a lot of flexiblity at the cost of intuitive syntax. These can be viewed as a middle-layer on top of the graph engine. PyMC3 always shined at being beginner friendly with easy syntax, so can be seen as targeting the top level.
Not sure the existing syntax could work with pyro, however, as the model creation needs to be rerun I think.