I can see a space for something that's largely a DSL with restricted syntax for defining objects, but offers hooks and escapes into code, itself with syntax and

I can see a space for something that's largely a DSL with restricted syntax for defining objects, but offers hooks and escapes into code, itself with syntax and abstractions designed to be as graspable as possible, for defining behavior. You could give it to designers and let them focus mostly on building games, not on learning a general-purpose language - think something like Inform 7, but with a different UX target.