My ideas: Diplomatic: Leaders who are smart in avoiding confrontation (opposite of aggressive) and take advantage of a relationship. +2 rating in diplomacy; 10% bonus in tech trade (exact figures need to be tested to avoid over- or underpowered); results of goodie huts as if one level of difficulty lower. Adaptive: Leaders who perservere and make the most out of difficult situations. +1 shield in jungle tiles and workable tundra tiles, +1 gold in workable desert tiles. Half cost building hospitals and recycling plant.