Just go for it. Free-Use sounds fun, you could go almost anywhere with that premise. And I for one would be interested in reading it.

Don't hesitate to write something because you're afraid of how people will react. Just be creative, write what you enjoy and enjoy creating it. Who cares what other people think.

Speaking for myself, I write the most overblown, overlength porn fic Guro may have ever seen a few days ago. It was riddled with missing words, ran on for ten chapters, and had the lamest Guro finish in history. And nobody gave a f***.