Current Part Automation behavior
Currently you can add automation lanes within Instrument Parts pointing to automation parameters of the connected VST Instrument, called Part Automation. Part Automation is exclusively available for the VST Instrument connected to the Instrument Track. To automate a parameter of an insert residing on the audio channel of the VST Instrument you have to add an automation lane to the Instrument track or an automation track.
Part Automation can be found here:
Extended Part Automation (primary request)
I think it would be great if we could also add automation data for VST inserts residing on the audio channel of the VST Instrument as Part Automation. So extended automation and musical data are residing in one Instrument Part.
Global Part Automation (secondary request)
Since it often happens sounds triggered by an Instrument Part are modified further in the chain (e.g. by bus processing, FX channels etc.), it would be very convenient if an Instrument part can contain automation data of ANY VST automation parameter available in project. So you can keep all relevant automation data in one part. With global part automation you can basically create automation clips with Instrument parts.
A part on Instrument track #1 contains Part Automation to an insert residing on the audio channel of Instrument track #2.
To keep it simple for people who don't need this, it might be a good idea to create a tick box for the Part Automation dialogue where the user can choose to show Global Automation Parameters, to view all available automation parameters in the project (disabled by the default).
Audio Part Automation (tertiary request):
Additionally audio parts (so merged audio events) could also benefit from Part Automation. This way (global) Automation and audio data can reside in a single clip, just like it's done with Part Automation for Instrument Parts (primary request).
Audio part automation could be even stronger when it is combined with the possibility to automate Event FX parameters as requested here: Can we please have the abilty to automate event fx??