What about a specific warning on the actual file?
Pardon me if someone already proposed this. A general site warning "Files here may contain malware..." is useless. Instead, scan the files for nasties! Then stick an insect icon on each file that comes up positive. This allows the informed and brave to download them if they have sufficient cause, while keeping those of us without an airgapped sandboxed throwaway PC to steer clear.
Now that I think of it, a Search filter could be offered as well to include or exclude files with bugs.