Geometry: will have the possibility of having several models loaded for each Geometry, and will switch between them based on distance. This can probably be contained entirely within the Geometry class, with at most a single selector argument.
Textures: will have the possibility of mipmapping, and/or multiple textures (possibly all the way down to vertex colors) again implemented entirely within Texture and selected at render time.
Tesselation shaders: adaptive subdivision based on camera distance.
This will affect several systems: