Turn off palette entries for chunks which don't use them.

Alpha clipping on the card?

Multiple material maps or individual coverages per material (vs only 1 or 0)

Perlin noise disturbance to the alpha map.

Quadtree caching for large terrains (plus memory mapping)

Look into upchain lazy evaluation on the QuadTree

Give heightmap resampling levels.  (Procedural terrain, functional callback)

Vis Hierarchy 
