Your whole point is undercut by the existence of Portal: Revolution, Portal: Mel, City of Heroes, etc. There’s a way to do fan creations that’s supported by the IP holders and ways not to do it.
I don’t expect indie devs to be experts at the law but they can hardly be surprised if they go outside the boundaries set by the IP holders and then get a C&D.
Your whole point is undercut by the existence of Portal: Revolution, Portal: Mel, City of Heroes, etc. There’s a way to do fan creations that’s supported by the IP holders and ways not to do it.
I don’t expect indie devs to be experts at the law but they can hardly be surprised if they go outside the boundaries set by the IP holders and then get a C&D.