Maybe we could have a comment from the Steinberg folks on this? ("Pretty please, with sugar on top?")
Seeing that this has been "on the plate" for a while, any information, good or bad, is better than no words at all.
Imagine HALion with the VSTi sidechain input, a realtime audio oscillator, or even better an audio input buffer being the actual (grain) sample source. Now that is something worth dreaming about.
With Note Expression (VST3.5), individual notes contain their own set of controller data when played polyphonically.
VST Expression, Steinberg VST
Cakewalk Sonar X3
now supports VST3!