You don't have to listen, but we're talking details here. All of Outerra's surface details are procedural. Technically so.
You don't have to listen, but procedurally generating a planet from the ground up (literally) is a lot more complicated than modelling a landscape by hand and then giving it a PG overlay for detail. Outterra just has to render mountain where there is supposed to be mountain; field where there is supposed to be field, sea where there is supposed to be sea. In ED the planet generator also has to decide where there should be mountain, field and sea based on real-life geological principles. For all types of planet. And they did that in nine months. Whereas Outterra has had five years to get just one data-modelled planet looking right.