I have just thought of an idea that I hope will be extremely dwarven. The idea is:
What if enemies sent secret agents in with your immigration waves?
After all, noone checks your immigrant's intentions when they arrive. So why not have some interesting things happen with them? I'll also throw around some ideas that would make both social dwarves and fortress guards useful for something.
SUMMARY
Spies, thieves and saboteurs will all arrive in immigration waves. They may or may not have a profession. To get you off track, they will also do some of the work you ask them too. Another thing to note is that all three carry "Concealed" items. This means they cannot be seen on the dwarves (or possibly another race, if multirace fortresses are possible in future) inventory screen. Spies and saboteurs would always be attached to a civilisation, but thieves can also be freelance.
SPIES
Spies are devious dwarves sent by the enemy. While they may do the things you ask them to and look like a good little dwarf, they will take longer breaks than usual, and spend the time wandering around the fortress. Their aim is to build a mental map of your fortress, counting the numbers of military and locating as many traps, levers and buildings as possible. It will also try to blend in by talking in the dining hall, but dwarves with good "Judge of Intent" skill may realise something is amiss when talking to him, in which case the spy is discovered. Fortress guards may also "arrest" a dwarf acting suspiciously, and take him for questioning with the Captain of the Guard. If the Captain of the Guard has good enough social skills, the spy will also be uncovered.
How do spies dissapear?
If a spy is not discovered by the time he has explored the fortress as much as he intended to, he will simply wander out of the front doors of your fortress. After a while, he will be revealed as a spy as your dwarves realise he is making a run for it. This means your military becomes hostile towards him, but by the time this happens it may be too late, and he may escape anyway. If he escapes, he will inform the race who sent him of the traps in your fortress, allowing them to avoid them, as well as giving them a rough idea of how big a siege to send. Expect a large siege if you let a spy go.
How do you stop a spy?
If a spy is discovered while socialising, he will draw his concealed knife (he will also reveal a hidden "Knife user" skill). He will then stab the person who discovered him, and make a run for it out of your fortress. He will be prepared to stab anyone in his path, but unless he's already close to the exit of your fortress it's more than likely your military/ fortress guard will intercept and kill him. Discovering a spy this way can lead to injury or death, however. If he is discovered by the captain of a guard during questioning (members of the royal guard are always present at questioning) he will have two options. If he thinks he can take on the captain and any members of the royal guard who are there, he will draw his knife and attack. If not, he will surrender and be taken for jail, and incarcerated indefinately (or hammered, if you have a hammerer).
THIEVES
Thieves are similar to spies in some respects. They can be sent by an enemy to help gather for the cause, or they can be a thief all on their own. All thieves carry a concealed sack, which they will put items found on the floor (they will not take any raw materials such as stone, and have a preference for light objects) into. The sack has a fairly large capacity, and they could easily walk off with several thousand dwarfbucks of items if undiscovered. A civved thief getting away may also mean a siege from that civ is on its way. Thieves are captured in a similar way to spies, only if a fortress guard actually sees a thief steal something (thieves tend to avoid fortress guards though) the alarm will immediately be raised.
How do thieves dissapear?
Thieves dissapear in a very similar way to spies, and once they are a significant distance from your fortress, they will simply run off the map. If they escape, your items are gone.
How do you stop a thief?
A thief is stopped in a similar way to a spy (other than the fact that a fortress guard can directly rumble them) but a thief carries no weapon, and will simply make a run for it if discovered. If he is desperate, he may also drop his sack, which can be rather heavy (a slowed dwarf can also indicate a thief). If a thief is surrounded or seriously injured, he may surrender, leaving him at the mercy of your fortress guard and hammerer. A thief can also wrestle, but is only likely to do so against a weak, single fortress guard or a civilian in his way.
SABOTEURS
Saboteurs arrive in a similar way to thieves and spies, but will carry around concealed building destroying equipment. He will, during his free time, try to dismantle or damage buildings, start fires and pull levers. A saboteur can be a serious threat, and so a strong fortress guard is essential. It is also worth noting that a saboteur is often encumbered by the weight of the equipment, so he may be spottable by you (you may then take matters into your own hands).
How do saboteurs dissapear?
Saboteurs will stay in your fort being a nuisance/ causing chaos until discovered.
How do you stop a saboteur?
Saboteurs can be stopped in similar ways to a spy, and if a guard catches him breaking something, he will raise the alarm. Bear in mind, however, that saboteurs will avoid guards like the plague. If discovered, the saboteur will either surrender, and let the fortress guard deal with him, or if he thinks he can get away, will drop his equipment and try to escape. Later on in the game, as your civs descend deeper into war, saboteurs can carry concealed knives and even swords, and a legendary swordsman saboteur suddenly on the loose is not out of the question. Fortress guards would be required to apprehend them.
So, what do you think of these ideas? I thought they might make the game a lot more Fun, especially later on, and give the fortress guard something to do other than get injured, and the hammerer something to do other than inhale molten rock.