Heightfield-based erosion is already available, and that's what pretty much every other landscape modeling system has. This works fairly well, it's just limited to the area of your heightfield, so it's not appropriate for planetary scale. The only one who seems to have gotten a handle on a workable procedural erosion, which could theoretically cover a planet, is Dmytry Lavrov, who created the volumetrics plugin for MojoWorld, but his procedural erosion system was never made public. As far as I know there are no other procedural erosion systems available, not even in academic research. The "alpine" shader has some visual resemblance to an eroded mountain, and additional shaders of that type are a possibility. Full procedural erosion is a pretty significant area to tackle though, and it's not likely to be an area of focus within the year.
A shore/surf system is a much more strong possibility, and something we definitely want to add sooner than later.
- Oshyan
