Transform filter should work on all types of data
Currently the transform filter only works on data types that subclass vtkPointData. However, the transform filter should work on regular data like images and rectilinear grids too. Both of these types of grids can be translated or scaled by changing the origin or spacing between points. If some other transform is given (such as a rotation), then either of these grids can be converted to a vtkStructuredGrid (a curvilinear grid) with no more overhead than one would expect from a filter than generates new coordinate arrays. (In fact, it would be reasonable to always convert the grid to curvilinear.)
This would be a welcome addition! Particularly, it would be useful to re-orient images (invert the "y"-axis, for example).