Ok, here goes with another suggestion:
How about a object program extension?
As pixel shaders & vertex shaders allows substitiution of certain functionality in the pipe, I propose a higher level programmability for programming things such as N-patches, tesselators, procedural objects etc.
I would like to implement a level-of-detail (LOD) system that allowed artists to generate high quality objects without having to go too much into detail ("too much" is of course a subjective term).
Lowpoly versions could be tesselated with a displacement/bump map in respect to the "closeness" to the camera. Tesselation could be adjusted with perlin noise, fractal or other functions to allow high degree of zoom.
These objects micro structure would be dictated by materials (read: combination of programs and shaders).
As for the implementation they should replace whatever streams the vertex arrays to the vertex programs (or they can generate the vertices on the fly).