I agree wholeheartedly. If VTK had a well-defined and introspectable C ABI, then the bindings of many languages (including Python) could be made to be very lightweight. Instead of wrapping every single VTK class for Python, we could just have some generic translation code that handled all classes. Still a very big project, though.
Speaking of MATLAB, many years ago I worked on MATLAB-Simulink wrappers for VTK and ITK. It was a fun project, but there was very little interest from the community. Fortunately I was able to fold some of the effort back into the VTK Python wrappers.