There are lots of interesting ideas you have there. It's true that the project could be expanded a lot. However I prefer to keep it nice and simple, and also keep all creative control myself. So my intention for the moment is to keep it as more of a fun hobby project that I can work on in my spare time.
Thanks for the links to the level editor assets! I had't seen them before, you're right that the first two seems most promising. I will look into this more when I have the time.