Maybe do Civ specific great leaders based on there traits... like Great Scout having radar, hidden natl, all as road.
great industrialist finish build function
great warrior for militaristic would be the strong unit i mentioned earlier
great econo i mentioned earlier for commercial (brings a lot of cash)
upgrade a leader to a special ship for sea faring?
upgrade the leader to a settler with 10 pop points for agricultural to increase the pop (only give join city function)
great religious leader too
any other ideas?