Simply that it would be useful if you could set vertex atributes other than texcoord0 in script (it may already be possible, I really dont know).

A D3DXMesh has a number of vertex attributes, defined in the mesh declaration or vertex format. This can include a given number of texture coords, colors, etc.

In d3d you can chnage the data in the mesh by locking the vertex buffer and writing to it, this is how vec_to_vertex and vec_to_uv work.

It would be helpful if more of this functionality from D3D was exposed in script. You can store lots of useful data in vertex attributes, and in relation to this topic, you can store colors that can be used to blend textures per-vertex, without the need for additional textures in the blending shader.