I was looking for both.
For one, the plugins should be easier for the basic users, ie, given a list of integrated ship, and subships, here are their positions within the integrated ships, and the directions/speeds they should use to properly separate/integrate. The rest should be reasonable defaults.
For example, music, is it a cutscene or not, should there be a different reintegration sequence? All those things are more or less "advanced" features.
I'm still thinking on how to represent this, I would like it to be all in the ship plugin, but obviously, the more complex parts (say, user defined cutscenes) won't fit neatly in a ship plugin. And if you want the same ship to be allowed to split into some more types of ways, then just a single entry in the ship plugin won't do.
So a new plugin is needed. Perhaps I can do both, the ship plugin for the most simple case, and MVAMDef (or something like that, maybe more MVAMConfigurationDef) for others, it would allow you to inherit from it and override functionality.
But all this first requires some form of proper identification of ships, that won't interfere/has accidental overwrites.