Why do Controllers have to wrap VSTs?

Why do Controllers have to wrap VSTs?

I don’t really understand the VST design, but I wonder why the specification for VST4, might not include an ability to transfer data better between VST instruments and a controller keyboard. Wrapping VST seems such an ugly workaround. We need the tech IMO>

Should there be some kind of standard?

Whilst on this topic - what about Music XML and other standards, cant they be integrated too?

Z