Gabion walls don't need any kind of drains because they are porous throughout. Gabions can be customized to make them more useful in public spaces. Gabions can be filled with any heavy material--diverse stones, metal artifacts, obtanium, etc.
This contemporary curved bench seat in the landscape is so smart. Can you imagine relaxing and kicking back in the afternoon sun. The form would also work well with exposed aggregate concrete. If done in this treatment it would then double as a skatepark