Idea for new improvement

So I'm always upset at how the AI decides to pretty much ignore hills when your cultural borders expand, and I don't always want to use gold to fix it (I know BNW makes gold less of an issue late game, but if im trying to get early production, its hard to justify spending a significant chunk of gold on one square). So I was thinking of having a settlement improvement that can only be built outside your tile that, once built, would direct your expansion towards that tile. Maybe have it be unlockable with trapping or writing or something. Any thoughts