After several games i really think Epiphany is over powered. To test this i tried a game : Gifted,gigantic, 16 AI's.
I only colonized 3 planets, never built a war ship, always selected a scientist citizen (except for 1 worker). Traded like mad for techs to get me close to age of assention, used Epiphany promotions to due the rest (equiv to some 200000 research points) and won an assention victory in under 130 turns
