I think access to the transformation matrices could make sense in some situations. As game developer I know which objects are fixed and which are not. For a fixed object I need only one time the inverse worldmatrix, in a loop I would transform the eyepositon to objectspace and set them in the entity or material skills which are used as constant values (one calculation per model). In vertexshader the transformation would be calculated for each vertex, which could be expensive depending on the number of vertices.