Overall, I like most of the ideas even though it's clearly not a concrete foundation yet...
I must admit I have a few reservations about being able to be 'absorbed' into a Kingdom against your will... BUT that's what kingdoms do, right? So as long as there is possibility to FIGHT BACK, (even if a seemingly impossible fight) I'm ok with it.
I'll leave the details, numbers and all that for the more hardcore part of the community, so I'll just comment on some creative ideas/systems 'cause that's what I like to do most
So, let's go into a few of my crazy ideas! Remember - these are just some nice concepts that occurred to me when reading about the possible Kingdom system. Feel free to suggest more ideas and note that these are all CONCEPTS, they aren't made to be flawless or anything, just explore the potential of having kingdoms.
LORDS/VASSALS/MARSHALL
Whenever a village is 'absorbed' by the Kingdom, its Lawspeaker should become a Lord of that Kingdom. A Lord is a higher tier vassal, with some power on the politics of the Kingdom (for example, Lords can be claimants, something I'll discuss below) Lords can also be part of a council/moot, something I'll also discuss below.
The Marshall would be the 'hand of the king'; like what a chieftain was to a Lawspeaker in legacy.
CLAIM ABSORPTION/ANNEXING
Well, like I said, I have a bit of trouble with that. But it is also interesting and opens way for a lot of possibly interesting interactions.
I think that even though absorbing a personal claim or village is possible, it should be expensive (in terms of Kingdom authority). The larger the claim or village being annexed, the larger the cost. It should be expensive enough that big conquests or rapid expansion would open room for a Civil War, something I'll discuss below.
DEATH OF A KING
The death of a king character should be a big thing. However, kings should also have some sort of aura of empowerment to encourage them to leave their thrones. Maybe they could buff his soldiers, maybe he could slightly increase the Scary Siege Weapon speed, something like that - thing is: it should be cool to have kings participating in the action but also be a risky thing for the whole kingdom. Killing a king is, after all, something big. When a king dies, it should also bring the Kingdom to the point of a Civil War (by dramatically lowering its authority).
CIVIL WAR
The Civil War would be a state where the leadership of a Kingdom could change. This could add a lot of dynamic and fun/great stories to the game. Just like people can claim the position of Lawspeaker when a village authority is low, any Lord/Vassal should be able to claim a Crown from the central Kingdom Object IF the Kingdom Authority is below a certain threshold. When a Crown is claimed, the person is recognizing itself as a claimant to the throne. When that happens, all the XP from the villagers of that Lord (that would normally go to the Kingdom) will instead go to its own personal "Claimant Pool". Claimants can also "Ask for Support" (right click command on others) to add them to their own XP pool even if they're not the claimant's villagers. All the remaining members of a Kingdom that doesn't belong to a Claimant village and have not supported any claimant will automatically support the Kingdom pool as they always did (which will count as support to the current king or their descendant if the civil war started because of the death of a king).
By the end of a timer (more than 24h so sieges can occur), the claimant with the largest pool takes the throne. If no claimant has a pool larger than that of the king, the war ends and the current king keeps the crown.
If a new king rises, remember that Resistance is not futile: You just need to kill the new king (loyalist royal guard, advance!) and a new Civil War will start, allowing for the former king to retake the throne.
Oh, remember: the kingdom is still 'open' for wars, so careful with political struggle as it will weaken the kingdom and leave it vulnerable to other kingdoms.
THE MOOT/COUNCIL
When formed, a Kingdom should have the option to set several 'rules' of that kingdom. Rules could include different punishments for the different crimes/scents, taxation (XP and some other forms of taxation that could be worked), trespassing rules for strangers/people outside the kingdom, even forestry or hunting rules, external diplomacy tendencies, etc. Rules should not remove the sandbox aspect of the game but instead create additional layers for the moot/council system to work. The moot could be formed by the 6 or less greatest Lords of the Kingdom + the King and their Marshall. The 'greatest' Lords would be defined by their village's authority or number of villagers.
The Moot/Council should be an event on a central object (the Council Table) which the members of the Council can or can not attend to. When the council is summoned (right click table), council members should have at least 1 or 2 hours to get there (so you 'activate' a timer). Every council member is notified and can instantly answer with "Will go", "Won't go" and "Won't go but the King has my blessing".
What is so important about the council? The council is the ONLY place where the rules of the Kingdom can be changed and also where Wars are declared, Peace is accepted, etc... This should be made as a series of votes called by Council Members. However, the King will ALWAYS have the final word - but here's the tricky part: for each member that says NO, if the King decides to go with YES, there will be a Kingdom Authority penalty. If the Lord refuses to go but says the "King has their blessing", this means that this Lord's abscence will not inflict authority penalty.
If they just can't go, they'll inflict a small authority penalty for every decision the King 'overrides' the council.
Politics, politics, politics
KINGDOM POWER
Some people have discussed how unworthy wars would be since everyone would just alt-vault their kingdom's valuables before an attack. Although this is true, there should be a way to mitigate it. So comes the concept of KINGDOM POWER. I've suggested something similar on the other thread, but here is the reworked version:
The Kingdom would keep track of all that is built and crafted inside of it, giving it an arbitrary value based on what it is and its quality - metals, constructions, etc. This total value would be called "KINGDOM POWER". However, for anything to count towards this value, it must be stored inside the kingdom territory and not inside character inventories. The Kingdom Power fluctuation is directly related to the Kingdom Authority - if it is kept more or less the same (there will always be some fluctuation as materials are spent, items are used, equipment is worn and lost, etc...), the Authority stays stable. If it lowers too fast/suddenly, Authority also takes a hit. So the kingdom valuables must stay inside the kingdom or the authority will be greatly reduced, getting below the point of a civil war or maybe a complete conquest (if ransacked by another kingdom)
CRIME
Although the 'security' of being inside a Kingdom is nice, it kind of goes against Haven & Hearth's nature. I don't like to think that you can be REALLY safe anywhere. So this is a little idea that maybe could spicy things up a bit.
Outsiders could build a 'Criminal Hideout' inside a Kingdom. The Criminal Hideout could be some type of house that leaves no mark whatsoever on the map (no pavement, etc) and is really difficult to spot. Yes, it decays - hence it requires constant attention/repair (should be cheap to repair but expensive to build).
IF you have a criminal hideout inside of a Kingdom, you'll acquire the right to trespass, steal (theft) and attack players (but not kill) inside that Kingdom. However, if you leave a scent inside the kingdom, you can only teleport to your heartfire from inside your hideout (or outside of the Kingdom), forcing you to return to your hideout after commiting a crime.
A Criminal Hideout has its own privilege control (like claims do) where the owner can define other people to use the same hideout.
Hideouts would 'encourage' kingdoms to patrol its own roads and territory. It should be possible to destroy one without a Ram.
COINS
Bring back coins
there are great suggestions of currency/coins right now in this forum board, make it so that each kingdom has its own coin by adding the name of the Kingdom to the coin. Let's say, if my Kingdom is called Wessex and I craft some copper coins, they'll be "Copper Coins of Wessex".PUBLIC STALLS
When Merchant Stalls are added back, also create "Public Stalls" - these should be empty stalls that can be occuppied by anyone and work as a merchant stall for that person for as long as their characters (and storage) are kept there. This would be a nice thing to build on "open cities".
FREE CITIES
I don't know how expensive will be to create a kingdom. Probably a lot. So maybe there could be an intermediary system (or something you define when creating the Kingdom) to create Free Cities:
Free Cities can't declare wars nor expand, but wars can't be declared on them either. They could be the ultimate trading cities with bustling, famous markets across the World.
.... Yeah, I quite fancy a crown, actually, if the king of a kingdom would like to make me his queen, then maybe I might come around a tiny bit more .... 
