Network rendering.
Flowing water (rivers, waterfalls, rapids, etc.)
Roads, rail, fences, etc.
Design heightfield by drawing contours.
Generate design map from user-designed 'primitives map' (e.g. plains, hills, mountains, etc).
Export 'shadow height map' option.
Vector/polygon based area definition for overlays and other operations
4).
Latitude-based climate variation (eg poles-to-tropics).
Preview option that generates only specific parts of the heightfield
5).
Strata-masking of erosion.
Radiosity mapping (e.g.
this).
Make water plane calc switch sea/lake (depending on edge conditions.)