Hello Tim, When Debian had less than 1000 packages it meant something to talk about "specialised requirements", and divide packages between extra and optional based on that, but that division has broken down now we have 50,000 packages. As I understand it, the current consensus is that the difference between extra and optional is only whether there are any file conflicts with other packages.
It would be acceptable, therefore, to change your package to extra or libpeas to optional. I agree with your reasoning for leaning towards the latter. -- Sean Whitton