The only use we had for RAS_StorageIM was to render derived meshes using Blender's mesh drawing. This is now handled as a special case in RAS_OpenGLRasterizer instead of in RAS_StorageIM. We are now left with RAS_StorageVA and RAS_StorageVBO. At the moment vertex arrays are still the default since our vertex array with display lists implementation is still much faster than our VBO code in a lot of cases. As we improve our VBO code, we can drop vertex arrays since Blender's minimum OpenGL version is being bumped up to 2.1, which supports VBOs.