Any examples of Domain game innovations?
One example is the very broad definition of a "magic item" and the way it interacts with the skill system. One could, for instance, define a title of nobility as an "alternative reward", a type of nonmagical ability that behaves as though it was a magic item. A title of nobility could then provide advantages, primarily as a bonus to certain skill checks (although a creative DM could build in other abilities), to help you navigate at court, or in your dealings with NPCs. Or you could establish a "spy network" which increases your odds of receiving certain types of rumors or other information, or a "merchant fleet" which could generate income. The possibilities are only limited by the imagination, and the amount of the bonus you receive scales with the resources you put into them.
Not only that, but you can build "item sets", where if you have certain combinations of items (say, noble title, a palace in the country, and rich lands) you could gain additional benefits, or improve the benefits granted by one or more of the items alone.
You can then attempt various types of moves as part of the domain game (on your "domain turn", or adopt a turn of phrase from Necropraxis), to expand your political influence, for example, or improve your estate, or gather damaging information about a rival, or defend against actions taken by a rival, and there is a baked in resolution system to resolve it based on your skill set and the advantages provided by the resources you have invested in. Or if you don't want to be stuck in the castle all the time, you can hire a chamberlain, or a steward, or a spymaster to manage things (and substitute their skills for your own on the checks).
And the mechanics are already there, this kind of use is already "legal", and there are precedents for the types of costs and benefits involved with the "items" and "item sets" I am contemplating, and how long such things last without upkeep, and how you can upgrade them. Also for long term effects, like bad weather, or famine, or disease in the village. And it scales; you could run a lesser domain game at lower level, as a vassal knight rather than a lord, with an unfortified manor house and a single village. For that matter, you could use it if one of the low level PCs inherits a tavern.
And since it is part of the magic item system, you can receive these things as a reward. So you aren't buying a spy network, you have an adventure to establish a spy network, and at the end of the adventure you get a spy network. Or you reach lord level and the lord gives you the title of marquis and the right to establish a castle and clear lands in the borderlands, but you have to pay for the construction of the castle (which gives you a bonus to intimidate your neighbors, making it more unlikely that your peasants will be raided), and you don't get the benefits of the land until the castle is built and you have cleared the area (clearing the area gives you a bonus to know terrain features, good places to hide or set up ambushes, etc., within your lands). Your land will support a certain number of knights or men at arms, depending on how much you invest into improving it, and how you go about doing so. So you can get more armies by getting more land or improving the land you have.
So the fighter has his title, and his castle, and his lands, and has probably hired some men at arms, and maybe granted land to vassal knights. Because he guards a border he is exempt from military service (unless the realm is under threat). He has only attracted a few peasants, and not much of his land is developed yet. He can hire someone to manage the estate for him, and go adventuring, or he can try to manage it himself.
But one of his neighbours has an eye on his lands and starts spreading rumors at court. This would be a bluff check (of either the neighbour or his agent) against the fighter's passive diplomacy to see if it succeeds that turn, but since the fighter has no presence at court yet the neighbour gets a substantial bonus. Pretty soon the fighter receives a summons from the king and has to go deal with the rumors. Since nobody ever wants to split the party, all the PCs go with him, and he leaves one of his followers in charge of the garrison. While he is gone, the neighbour tries to convince the humanoids on the frontier to raid the fighter's lands (diplomacy vs. follower's intimidate). If he succeeds, and the raids succeed, the fighter could receive a loss of reputation (penalty to social checks), or his land could be downgraded. Hmm, maybe it's time to invest in a better seneschal.
Fighter has dealt with the rumors and wants to return to his estate, but the party rogue wants help setting up/taking over a thieves' guild. It's only fair, he helped the fighter clear the land to establish his estate, but fighter doesn't want to be away from his land. How to they resolve this? Hire a seneschal, or hire henchmen to help the rogue? Or appoint the cleric as seneschal, since he isn't crazy about helping to establish a thieves' guild. Thieves' guild is established, tasks his followers to set up an intelligence network (cue proxy low level adventure with followers, or just let them make a skill check if you don't want to play it out). Meanwhile, the party tries to figure out who is spreading these rumors (the latest is that the fighter is consorting with criminals and supporting organized crime), and how do to that while there are still humanoid raids going on at the fighter's estate. Cleric comes back to the city to help the party, and the fighter hires a senechal who is better at managing the estate and rebuffing the humanoids than his follower - but unlike the follower he is not fanatically loyal, and the neighbour starts working to try to subvert or compromise him...
Basically you get this constant tension regarding what the PCs are going to deal with themselves, and what they are going to delegate to proxies, and which proxies to trust, and an action resolution system to determine the success of the various "off-screen" activities.
And the things the PCs get in the domain game - titles, strongholds, lands - have a concrete, mechanical benefit associated with them, so the party doesn't miss out on treasure by choosing not to go adventuring, they just get a different kind of treasure. So you are not relying upon the domain game to be its own reward, it is actually supported by the mechanics of the game.
