Example of combat engineering:
Units with harvest tree ability (logging, which is basically axe melee skill + knowledge of the procedure of logging (how to drive the wedge in to split the wood, how to TRY to make the tree fall where you want) + experience in the procedure of logging) + Twolls with fabrication + spare rope + rocks = trebuchet
If I remember there was a Nova program on Trebuchets and 2 teams built their 2 different full-size Trebuchet designs in 15 days. That would be 15 Turns in Erfworld, true, but if Ansom was smart he wouldn't have hurried to kill Parson. I mean what I really don't get about Erfworld is how QUICKLY they take down Level 5 walls. Without spells and without explosives and with only 40% of their planned siege engines still operational. Though it's kind-of funny that since Wanda is a Croakamancer a Siege almost won't work against her (units die from starvation or are killed earlier so their bodies still have some mass before they go) and are then uncroaked and don't need upkeep (though they eventually decay into dust so the siege still wins ... eventually). I assume units in Erfworld can still starve (what you're on a desert island and food magically appears to feed you every day?), and I assume that the food that appears before you is actually from the city's Granary/food storage. Now that Wanda can Decrypt ... a siege ... umm ... would actually still work against her because a famished unit would probably still Decrypt as a famished unit and would still need to eat even when Decrypted (let's try not to make Wanda's ability too overpowered, now, assume it's exactly like being popped again no cherry-picking no upkeep too) so ... siege = win.
I know full-time soldiers would be able to Drill to either increase or maintain their combat experience / level ... but what about the units that harvest the gems and the trees and till the farms? Those could be trained as milita.
Loggers -> Axe wielders, heck axe throwing is even a sport among fronteirsmen so if you convince the loggers that axe throwing is a competitive sport they could do it for fun in "off-turn" time (turn time being reserved for logging) and ... gahh my brain! Off-turn experience gain?! I suppose it's possible ... Parson was able to command Banana to do stuff off-turn ...
Farmers -> Spearmen (with pitchforks don't even need to upgrade those to spears if you don't want to though WHY cannon fodder them so easily when they are such (presumably) high-experience farmers?! Popping new ones inexperienced in the fabrication (with merely "natural" ability ... I mean for example popping a Twoll to be a Blacksmith that Twoll may have fabrication natural ability but he can't suddenly make mithril chain mail now he needs blacksmith experience to do fancy stuff!) is a BAD IDEA).
Traders -> Rangers/Trappers (Traders who know how to survive in the wilderness can make longer trips in desolate areas, they practice melee if they're ambushed and they practice bow if they are sniped by higher-move ranged unit or aerial ranged unit ... Ranger is obviously what comes from that skill set) Ranger may get Tame Animal skill bonus because of his experience doing that (capture live animals to sell, has time to study them alive though perhaps not tame them much unless he also wants to tame them before he sells them - maybe Advanced Ranges do that or something) and Trapper may get bowmanship skill bonus because of his experience doing that (since he used the bow more) though both get set Trap skills since both need to trap animals after all (Ranger may use rope trap that yanks animal up by leg(s) so it's non-harmful or if he's really fancy sleep poison the animal with a dart (maybe only for Adv. Rangers), Trapper may use Bear Trap-like device unless he wants a near-perfect pelt then he might resort to Rope or Impact trap and they don't learn Sleep poisons they learn deadly poisons of course), just whether they kill them or not decides if they're a Ranger or Fur Trapper ... and the advanced versions of both these classes get even better Stealth of course. The big question becomes well what happens if a unit decides to be a Ranger and Trapper (practice shooting animals with sleep-poisoned arrows he buys until he learns to make them on his own, tames them, then ... kills them and skins them ... wait he could have a part-time job skinning animals at Market for farmers who don't want to bother to learn the skill ... whew ...), so he practices bow skill, etc. basically practices all skills for both Rangers and Trappers at the same time (except for the make deadly poison skill which I guess he could learn on the side, not a bad skill to have you know ...). Sheesh these guys could double as stealthy ranged Assassins which could be how they fight so they'd be like Assassins except without Backstab and such, and could even Bounty Hunt with their sleep darts ... or work for Law Enforcement catching criminals with sleep darts. OK THAT'S IT classes are an illusion it's all about skills and abilities. Just like level is an approximate summary of your stats, your "Class" is a summary of what you do. Heh, this pretty much proves that "classes" aren't visible to people in Erfworld and they have to ask (unless they assume the guy in Monk robes with the cross is a Monk y'know), since classes are an illusion. The only thing that is visible when you meet a total stranger you've never heard of is probably their level (how else could you find out their level without knowing all of their skills and how good they are at them and their stats and ... yeah their level has to be given to you automatically) and hope they aren't using Foolamancy to appear to be lower level. Everything else has to be discovered and discoveries are automatically recorded for you (just like in Nethack).
All of the above units must exist because they work OUTSIDE of the city so they need to be in the game for enemies and outlaws to fight with to make a more in-depth game.
Units that work inside of the city ... well we already know a Twoll was assigned to become town Blacksmith at Gobwin Knob, so obviously there are jobs inside of the city. I just don't know what to make of Sizemore's comment that the city buildings are there to "just be the city." Maybe the number of buildings (even if they're empty) and if you have food or not effects popping rate of new units but that might be about it.
Immigration is pretty obvious, only Duty might prevent units from immigrating against the will of their Overlord (if they have one) ... LOL Parson invents Propaganda Foolamancy spell with Gobwin Knob's Foolamancer to fix that! If the units are Barbarians then, well ... they can do whatever they like but their Duty is not assured even if you let them immegrate and even if they honestly "swear allegiance." Though honestly swearing allegiance probably gives like a tiny +1 to duty due to slight guilt factor if they break their promise.
I just recently learned in Macroeconomics that the US is losing 2% of its jobs every year due to improvements in technology/efficiency. So the economy could be growing but if that's less than 2% we'd still have rising unemployment (exactly what's happening right now), but the economists hope that this is the turnaround and the US will get that economic growth above 2% within a few years (or a little sooner maybe if we're lucky and economic policy speeds it along). It's pretty obvious that units can't fabricate everything from the start, they have to become Masters in their craft. And Masters don't necessarily know every skill in that craft (very similar to You can Never be Level Infinity). I SWEAR Stuffamancy IS Research in Erfworld (how else is it "thinking up something and ... making it?!" That something could be from any magic "discipline." Hehehe yes just like Gordon R. Dickson's Dragon Knight Series, when Magic becomes common it becomes Technology (ex: Dollamancy is so common now it's kind-of stretching it to call it a magic discipline ... it's really more of a technological one)). When Magic REALLY really becomes a technology is when creating Artifacts that automatically do some spells (ultimate version of common is something anyone can buy that is automatic practically zero training needed) and intimately assist in high-level spells in that discipline can be done (for Thinkamancy - hard example - that could be ... a cyborg brain implant that can Teach You Kung Fu? You get the idea ...). Parson has a ridiculous X-factor in Stuffamancy not only because he's intelligent but also because he's from "the future." He's probably a Epic-level Stuffamancer by default simply because he knows about simple stuff in the Industrial Revolution like Production Lines (could improve Twoll fabrication a lot), that automated machinery can go beyond just Mills and progress to automatic weaving machines and on up (so you don't have to waste hardly any Pop to weave stuff that turn), and that he knows how to make electricity (how batteries work, and might be able to muddle around until he gets capacitors to work) etc. Depends, really, on how much Parson can get other Erfworlders to help him ... Parson way back in Book 1 makes a joke about making a Quantum Computer's qubits out of marshmallows, hence "marbits." So I figure Parson has a general idea how to recreate a lot of the modern world but no idea of the details since working at Kinkos (delivery? I Googled Kinkos and that's part of FexEx ...) has not given him an extreme depth of knowledge in a engineering/science field. If we're really lucky Parson is a minor Medieval (everybody except the Dwarves) and early Industrial (for the Dwarves) history buff since that would improve his tabletop fantasy games.
However, unlike the US, Erfworld might just give an Overlord enough Duty leverage to order his units to not be homeless (at the very least to join the military if it's really really hard to find a job even after training in skill(s)). Of course, the whole Trade can be Good because that Allows more Specialization which Allows more Efficient Production (ex: 1 guy with no training on a desert island trying to survive attempts to use herbs to ease his pain or help with infetion = he's alone he doesn't trade and he's likely to eat something poisonous because he's clueless about herbs he hasn't had the time to bother with them until now he's hurt vs. a professional herb gardener that knows hundreds of herbs and their properties and how to grow them but needs to buy his other stuff from other people = lots of trade and efficient production) ... that applies to Erfworld. Whoever can be friends with the Magic Kingdom gets access to loads of Specialists in loads of magical disciplines which really helps out and all that jazz. Whoever's friends with the Woodsy Elves gets a bonus to Woodsy stuff. Whoever's friends with tunnel-dwelling species gets a bonus to tunnel stuff.
So the question is how much longer will the Magic Kingdom hate Parson when they find out that he is a Stuffamancer (if the Magic Kingdom allies with Gobwin Knob's enemies there could be a serious fight)? Will they feel threatened by all of the Artifacts that Parson might be creating that are making them "obsolete" (of course they aren't really they're just automating lower-level spells and assisting to allow even higher-level spells to be created). The number of new higher-level spell job positions overcomes the number of lower-level spell job positions and the Magic economy grows (How else is the World Economy growing right now? Unlike the European Colonial era we aren't exploiting vast new natural resources.). That's the whole argument about how taxing pollution (ex: CO2) a little won't hurt the economy it'll create more jobs than it costs as it accelerates technological research (creating both research and high-tech enviromental jobs) in that area, though taxing pollution can be unfair it doesn't treat all businesses equally - ex: oil power plant vs. the zillions of Geothermal power plants in Iceland (>50% I think it's like 70% or 80% of all Iceland's energy comes from renewable resources), Geothermal power plants aren't CO2 taxed at all but oil definitely is.
Though if Parson gets his hands on Uranium and centrifuges and finds a solvent that dissolves uranium ... he could at great expense isolate U-235 and ... well ... bring enough uranium together and it'll chain-react ... boom ... the Magic Kingdom would be scared of THAT now ("A Spell over multiple hexes? Impossible!") that could get them to excommunicate him.
By the way, Gobwin Knob is really lucky. It's got Geothermal Power up the dormant volacano ... did you know that Iceland is the largest producer of Aluminum (costs a LOT of power to electrically deoxidize) in the world because power is so cheap there (because Geothermal there is so cheap because the heat is so close to the surface in Iceland)? If an Industrial Revolution does kick off in Erfworld, Gobwin Knob doesn't need oil (import from other countries which hurts national security or be lucky and have large but limited reserves yourself), they've got renewable geothermal energy, which is by far the easiest energy to get with low technology, easier than even coal because for coal you have to keep mining and transporting it. The only things Gobwin Knob may not have is certain ores/minerals/elements and probably a distinct lack of trees in the surrounding area since the volcanic eruption probably killed them. The soil is rich, though, volcanic debris is great fertilizer. And since certain seeds (ex: sequoia tree seeds) only germinate after a fire (ex: Fire-dependent ecosystems in the United States), so the vegitation might return faster than you'd think (though not as fast as brushfire ecosystems that have common fires so fire-adapted plants are common).