Question

Always wanted this in a DAW. Basically a you add a fader into the mix console (similarly to a VCA) and this fader can be assigned to any parameter or CC in any plugin or virtual instrument. Would allow for very quick and convenient control of plugins while mixing. Wouldn't need to be limited to faders either, other controls could also be added to the strip.

Answer 1

Could be added to VCA groups to tell which parameter it is to control - you can make one VCA for other things but volume.
I think fully functional VCA groups are like that. It is more like VCA Fader today.