"2. Game balance: The part that is giving us the worst trouble. We more or less agreed on the buildings and army sizes; the base buildings are added (in an early draft kind of way), but we can't seem to be able to reach good results (which I define at the moment as leaving the AI to fight the Rebellion on their own and having about a 50-50 chance for each side to win). There are a number of problems that prevent it, such as the difficulty for the rebels to rack up decent warscore against the juggernaut that is the Iron Throne. If you guys really want to know which part is the most crucial at the moment, this is it. You can help by reading the posts in the Balancing subforum, making your own tests, trying your own solutions and contributing your own ideas."
One idea I have is to for a negative relationship penalty for vassals for each independance war being fought so rebellion becomes almost a snow ball event where more vassal take their opportunity to rebel when the Iron Throne is at its weakest.. Say -5 per independance war and -20 Iron Throne claim war. This would reduce the opinon of the Reach and Westerlands to the Iron Throne thereby reducing levy sizes, it would also be more realistic as my intrepreation way the Lannisters sat on the fence and only joined the rebellion towards the end.