Hi, thanks for your interest. Advanced layeredimages are not part of our scope right now. Though I will put it on our list.
We are currently looking at the requests from the user base to decide the roadmap. We had planned on having that done last week, but we had another project at work that ran late, so it will be coming week. We have asked our users to suggest and vote on features, to prevent people opting stuff that is either already in or doesn't fit with the way the flows can be defined and would require overhaul of important parts. As said, next week we should have a new public roadmap (the previous was when I was still one person coding).
I myself use InViNode to build my games, so do some of my friends (and plenty other people now). Would be bad to let down my friends by not maintaining and developing the app further. The application is also available on Steam, so it would not be in my own best interest to stop development. For Rick it is a bit different. He joined because he felt I made mess of some parts.
There are no plans for an API, simply because we don't see the use for it. The tool is to support beginning VN developers, or veterans that think more visually in their process. Perhaps we can put it on the list, but the roadmap currently already seems to become pretty full. An API would require architectural rethinking.
I would suggest to look at the roadmap that we publish somewhere mid/end coming week (23th to 27th).
Regards,
Draw Flesh Games