The general sequence I have, and see other players having is joining the game, looking around for stuff to do, getting acquainted to it, and after some time start playing with a little less anxiety. What does this mean? That if a player joins the game and there is nothing more for him to do other than message everyone asking for a Lordship, and possibly traveling somewhere (though he doesn't really know where to travel), he is unlikely going to easily get a feel of the game, nor it will catch much of his attention. If he gets his estate and gets assigned to an army, but fails to get participation in what happens/is decided, or foresee any chance of political rising, then he is not likely going to get very interested.Of course, I am talking about one kind of player, there are several, but I feel this one takes at least a considerable part of those who seek the type of game BattleMaster is included in: political strategy.
I come from eRepublik, a game which had high potential but was torn down into a cheap copy of Farmville and Evony, which has, if nothing else, a great political system and community. I made it a little politic/social lab, and for politic parties and countries ended up diagnosing the same problem as BM: they failed to attract players because these didn't feel like part of something, the community. eRepublik doesn't have the limiting factor that is IC/OoC separation, and the risks involved in crossing it, so some of this ideas might not fully apply, or will have to be changed. In the virtual country of eUruguay we had between 50 to 100 active players (fluctuating population over the years) and as the game didn't offer a good message system we used an outside forum (every virtual country does that) and a IM system, first was MSN, then we migrated to IRC, where most of the countries were.
The most popular and effective tactic countries used for player retention was messaging the newcomers (later the game implemented a custom message the Country President would be able to edit) and inviting them to the Country forum and chat. Such gave players means of communication much more efficient, and the possibility of knowing what is going on around them, allowing them to join ongoing discussions and to fantasize and plan. A game is not very interesting when you don't have a goal, or something to look forward to.
On kingdoms, I would give the same diagnose I gave to political parties: their greatest problem is that they were becoming sects ruled by a tiny amount of people who kept for themselves all the information. And those positions were largely stagnant. Yes, I know this is how a Monarchy or such is supposed to work, but even if the setting is medieval, the players are not, and the nobles kept "being" in those times because they had little choice, unlike the players. Rotation of players is a good form of keeping people interested and making your realm a successful and attractive one. Even handling out ingame-irrelevant positions is quite useful actually
It is a problem when rulers choose old people who might not even be that focused in the game or specific continent, just as a means of keeping power controlled, for they might end up losing the power the new players give them.
A way that both gives newcomers an idea of what is going on, what is being discussed and what he can look forward to, and also helps a lot in the organization of low-rank nobles is the ingame forums system.
My idea, based on a small game, is having different sub-forums available in the game. One sub-forum open to all Nobles (or just Knights) in the realm and above, one for all Lords and above, one for each Guild, one for each Religion. In one of the 3 worlds that small game had, with certainly no more than 200 players, arguably less than 100, there were 41 brotherhoods, and for such, 41 of those small forums. That tends to make me believe such are not a nightmare in terms of data consumption and such related problems.
Example of the forumThe idea would be that you get a button added, or in Information, and you get access to the sub-forums available to you. These, as an initial idea, would be those previously stated (Religon, Guild, Realm-wide, possibly a Duchy-wide one, and one only for Lords and upper). The moderators in the brotherhoods of the game of the pictured were its founder (called Grandmaster, title which could be passed on) and its selected masters. In this case the Guilds and Religions moderators would be easy the Founder and Elders, with the Realm sub-forum for the King and the Duchy for the Duke to moderate.
One could say that this reduces the intrigue possibilities as information tends to get more public, but I assure you that a game with such forums still have lots of intrigues and the likes. It does get more difficult for people to withhold information and such, but it hardly becomes impossible. The benefit of people players ignorant is much less than the player retention of not doing the same.
It can also be argued that it is not medieval at all. I do agree, but it won't be the first non-medieval option in the game, and once again, the improved communication makes up for that.
There best part is that everything can be kept IC, and everything can be roleplayed. I see it as quite a boon for roleplaying, actually. But that is just my personal view.