Per pinball, I've decided that we will probably not be adding additional support for media and metadata, at least not any more than already exists. For one thing, it sounds like it's trying to fit a square peg in a round hole, and with the media "rights" issues I'm hearing about, that sounds like a nightmare as well. So unfortunately, I've been scared away from dealing with pinball media, at least for now. It's a nightmare from multiple perspectives, and I don't believe the audience for it would be big enough to justify the effort at this point (at least not once people realize how much effort it takes to set it all up).
Good to know that with Pinball FX3 it is at least possible to launch specific tables. The question though is whether it would be possible to automate an import. If every table requires custom parameters, I'm not sure how we would set that up. I will experiment with it though.