I think I've played around 10 games now during the Aegon the Conqueror scenario and everytime Aegon fails to expand. He usually lose against Harren The Black and often goes directly against the Lannister-Gardener alliance which he can't seem to win. Usually Aegon just ends up with a little land in the crownlands and nothing more. Not a single game of those I've played has he or his sons managed to conquer even half of Westeros.