Love this mod! I've been playing as the high king of Skyrim and I think the Nordic Moot succession system could be improved to both be more accurate to the lore and more satisfying from a gameplay perspective.
Currently it is pretty much impossible to get your child to win the election without giving them a traditional Jarldom because of the -100 election penalty from not being a Jarl. This is not very accurate to the lore since according to ingame sources in TES V and the UESP
Article on the Kingdom of Skyrim, it was traditional for the King title to be passed down hereditary, with the chosen child of the Jarl usually inhereting except in extraordinary circumstances "acts of dishonor, particularly the appearance of cowardice, can lead to the recall and reconsideration of the Moot."
It is also a huge pain gameplay wise since landing your heir is such an annoyance. If you want to secure succession early on in your reign you need to give your child a Jarldom pretty much as soon as they are born in case you die early. This is even worse option in Elder Kings than in the base game. In addition to all the shenanigans from vanilla CK2 that landed heirs get up to (No control over education trait, maiming self with medical treatment etc.) You also don't get to choose which guild they join or which classes they train as. These are major features of the mod and it is a bummer not to be able to use them to their fullest if you want to maintain your throne under nordic moot succession.
My suggestion for a change would be to change the election system so that only Jarls and High King are valid electors in accordance with the lore. The traditional Jarls can still have a higher voting weight. The candidates should be the High King's close dynasts, the commanders and Marshall of Skyrim and all the Jarls voting in the election. The High Kings children should receive a major bonus to elect-ability and his/her grandchildren should receive a minor bonus Also remove the -100 penalty for not being landed. This should not be a factor in the election since it was common for the Kings unlanded children to inherit and was actually uncommon for the High King to grant his heir a full Jarldom. It would also allow a prestigious and talented commander or marshal to rise to power dynamically. Of course certain traits like Craven or Shy should make a prospective king much less electable and need to be played around. The runner up of the election could then recieve a strong claim which he or she could choose to duel for or go to war for through event to model the rise to power of some usuper kings like Ulfric Stormcloak. Succession would be much more stable this way as it was in the lore but would also allow an ambitious player or AI to bribe their way onto the throne or take it by right of combat or conquest. Overall I think it would improve the experience of playing a nordic King immensly.
Keep up the good work in any case and thanks for creating such a fantastic mod!