One thing I think about when visualizing dd output is whether I want to be looking at the simulations or the diagnosands – or both!

I could imagine a faceted graph with facet_grid(N~estimator_label), where each facet is a geom_histogram of the estimates, possibly colored by whether the estimate is statistically significant or not. That graph helps to show how the sampling distributions tighten up with N, possibly differently by estimator!