I've noticed the all the victories become possible at about the same time on gigantic maps. By the time your influence is dominant, your tech tree is almost done, and eveyone is afraid of you and will ally with you if you wish, and your fleet is strong to wipe out everyone who is left anyway. My point being that all the victory conditions are nearly interchangeable, and therefore exterranous.
I anyone else noticing this? Is it different on smaller maps?