There is a nice mechanism in the VST2 wrapper that allows you to implement the various Plugin API extensions that are defined for VST2. Unfortunately, there does not seem to be an equivalent for VST3 where the extension mechanism ist based on additional COM interfaces.
Has anybody done something like this, without breaking the VST3 wrapper ? I want to avoid that by all means.
Here is an idea, how this can be approached. I would subclass the VST3 Juce implementations. I would tell Projucer not to generate the VST3 project, but rather do my own class factory. This would be a minimal project, which would reuse all of the VST3 wrapper and augment the controller class with additional interfaces. This should allow me to continue to use the VST3 wrapper code unchanged, i.e. maintain the ability to do drop in update of Juce.