Are you setting someone up for failure when you start them out on a project with very little direction to see what they can and will do on their own? It might seem so, but that's true only if you judge their potential by what happens. In fact, it can be a very successful journey of discovery if you understand the process.
One thing is certain, they will surprise you. And you will learn from those surprises. You might learn that their ideas are better than yours. You might learn where you need to be directive. Surprises are where you learn.
Certainty is a comfortable thing. Direct the whole thing and you minimize surprises. Sometimes that's exactly what you want. It's a good way to implement. It's not a great way to improve. Experiment a little when you can.