It actually very generic. Many times its something u stumble upon. U see a village, u go there, but u see that there are monsters there. U can kill them if u wish, which will result in people settling there. No one tells u to go there and kill them. But sometimes its a part of the quest. Sometimes its not.
Outposts in Farcry unlock areas and new quests and its something u fight for urself or ur clan. In Witcher 3, u do it or not, its a choice. Clearing the area will only add more people who detest Geralt.
Also in farcry the consequences are not present. In Witcher 3, helping people will actly affect ur game later. Like I said, ur actions might destroy an existing village if u r not careful. So its not just clearing areas for villagers. Sometimes they are screwed coz of u.