Terrain height maps use lossy compression, which causes land spikes around sharp slopes of terrain. The amount of data for the land height must be minuscule compared to all the other data in the scene these days. Make terrain lossless, and allow true WYSIWYG editing of the terrain height.
Notes:
This would require a server component for physics as well.
This would require a step where the current lossy height map is baked down to a lossless height map.