C7-Game
Barbarians Try to Attack Your Units and Destroy Your Roads and Cities
Instead of wandering around aimlessly, barbarians should seek loot, from your and other AI civilizations.
They should walk towards your cities, and generally try to be as much as a nuisance as possible.
This could be with individual units, or with small groups of them. I like the idea of having it vary a bit by tribe - maybe this tribe just attacks Rambo style, but that other tribe attacks less frequently but with some coordination. Kind of open ended, but more interesting than "beeline to nearest city" is encouraged. If they find the city is defended, but some Iron is available to pillage? I'd take the easy target if I were a barbarian.
This one has a PR, there were a lot of things to address on the PR and that's when my availability went down and I never got around to finishing the requested changes on the PR. So it's still open.