Just going to post what i believe is personally quite wrong and frustrating with the Mod.
The Mod really suffers from boredom after the initial start scenarios. The real problem is that the Mod is basicly the Holy Roman Empire in vanilla and every so often you have Dukes who rise up and rebel and you simply have the emperor put the rebels down and continue on. Except in vanilla the HRE is surrounded by other enemies, kings and possible problems that could throw it off.
The biggest problem is the fact that controlling or taking control of the Iron Throne is as everyone says, game over. It's boring, it's non progressive and it's really easy to marry off your siblings or offspring into high alliances with the other LP's to ensure your continued dynasty and reign.
Having any real Megawars like roberts rebellion or the war of the five kings is so rare and really never plays out that way. The entire Mod really depends on the megawar system tacked on with cool events and a few random events. This is the Mods biggest problem is the Megawars don't play out how they should be. You need to make this game feature more rebellions like Roberts, or the five kings. What you end up with is a matter of choosing sides to defend the king or not to. There's no flavor, it's not interesting and it's beyond easy to push eitherside into the players control.
My other problem is theres nothing that opposes the Iron Throne. If a LP rebels and actually happens to win and gain its independence it's really only a matter of time before the Iron Throne retakes it under it's control. I've never had a game where independent kings remained long. This is really due to no pressure on the Iron Throne, the only focus the Iron Throne has to worry about is revolts and marrying off smartly.
Dukes and Counts are boring to play as and have received no love

. The Counties have no claims on anything but a few territories, and the Dukes are bland and boring. There's nothing interesting here, and convincing people to join your plots is very difficult simply because the LP's are established so deeply and are generally in the positive ratings. One of the few Dukes that hold any interest is Rhaegar, simply because hes Heir to the throne at the beginning, hes a famous Dynasty and he has some of the few ships. Dukes and counties need some love. It's really boring playing as a duke or county in a empire where the empire faces no outside threat or real impact. As a duke/count your sole object is to go with the flow and slowly marry and assassinate your way to the top.
It's gotta be pretty clear by now that the game lacks continuation. It's more fun to stop after 100 years and start the scenario over again than it is to continue. The problem is that Westeros and the Iron Throne face no outside threat. It's too easy to the King to control the LP's simply because thats all he has to worry about. Sure you're adding in Wildlings but i don't see how this will be a huge effect into this. Don't get me a wrong it's a good step in the right direction but won't cause enough stir up with the Iron Throne to effect the balance of it's control enough.
You need events, you need things like Daenerys in the background building up a army, you need random mercenaries destroying the country and land. Westeros needs to be unstable, it needs to be interesting, wild and evolving. Becoming King of the Iron Throne should not be game over, you should struggle to control the LP's and keep order, not sit back and marry off your offspring to ensure your global control.
TLDR? :Add more events to effect the Iron Throne solely, which in-turn will shake things up with the LP's ensuring continued interest and a constant change in Westeros. Also make Dukes and Count's not so boring.
P.S, love the mod still.