From a seasoned player of the TW series, what worked and what not; I'm placing this here but it's a broader discussion and what I think went wrong with the provinces system, why and how it feels compared to previous systems. :
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Rome TW:
-single type of settlement, growth based on a predetermined value, taxation levels and a few buildings
-1 building per turn upgrades
-single unit per turn, with top units requiring multiple turns (slow gameplay)
-walls and streets required investments
-capital can be moved, distance from capital decreases public order
Opinion: In its simplicity, this worked just fine. Main cities would develop faster than others, the player had complete control on which to develop and how, which generally would result:
-high growth settlements being developed on all types of buildings and providing military
-low growth settlements being developed mainly on economic/public order buildings, then cultural, then sanitation.
Religion had a marginal role as it boosted either the military, or the economy, or the public order, thus can be counted as one of them. Streets are a must in every settlement, walls only in defensive spots.
BI:
-religion now is a factor and religious buildings do the conversion, with effect on public order
Main downsides: settlements are all the same, anyone who isn't Rome lacks the 3rd tier street, Easterners and Barbarians lack second tier streets, Barbarians lack non-wooden walls, magnifying a clear ranking in terms of civilizations. Some are far ahead than others.
Rating 8/10
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Medieval 2 TW:
Basic same system as Rome.
-Single type of settlement, growth based on a predetermined value, taxation levels and a few buildings
-Streets and walls require investment.
-1 building per turn.
-Religion plays a factor in public order like in BI, agents help spreading it.
-capital can be moved, distance from capital decreases public order
Main differences:
-multiple slots for hiring units
-castles and cities
Opinion: the castle and cities system did not work well. Castles had a fixed tax rate on normal, which would result in characters being set as governors for them becoming ''poor tax farmers'' and receving a ton of bad traits. Thus you'd never want to keep any character in a castle, only in cities. Cities also had a ''free upkeep'' for a higher number of units (up to 4-5 if I remember correctly) while castles had 1-2. So not only you'd want to avoid keeping characters in castles, but units too, making them virtually undefended all the time. Castles also had a public order bonus, so you could actually leave them undefended. A spawning garrison, something introduced in later TW games, would have helped this system immensely, making castles harder to capture and a bulwark of defense they were supposed to be.
Finally, the AI never developed them well, focusing only on walls upgrade.Lack of economic value meant that the AI was more than eager to give them out in exchange of peace, something that could be abused and you could get 2-3 castles for a peace.
It also had a major impact on the type of armies the AI created. Since it preferred cities and didn't develop castles properly, the AI would spam low quality spear militia for most factions and you'd be facing mostly crap armies, unlike Rome TW. To exacerbate this, militia-mainly armies greatly favoured the 3 factions with the best militia in the early game, the Italian ones. So you'd have Milan overruning France with Genoese crossbow militias, Venice overruning HRE, Sicily overrunning the Byzantines just with Italian spear militias. And that alone was even further exacerbated by the fact that those 3 retained the AI of the 3 Roman factions of Rome TW (Sicily-Scipii, Venice-Brutii, Milan-Julii), making them by far the strongest in the game.
For the player, it played mainly the same as Rome:
-high growth cities develop both economically and military
-low growth mainly economically
-few castles for top units
Rating 5/10
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Empire TW:
Evolution of the castles and cities system.
Now there are two types of settlemens:
-large ones with multiple types buildings, extra like historical palaces, admiralships
-smaller ones with a main government building, walls and streets. The smaller ones can be developed either militarily or economically.
-multiple buildings upgrades per turns, just like multiple slots for units creations
Standard settlement management:
-all natural resources are now not only visible on the map but can be interacted with by invading armies as ''minor villages'' that the player can often develop according to his own needs, colleges, religious, workshops
-walls and streets still require investments but all factons have the same, eliminating the tier type of Rome
-religion works sort of the same way as previous titles
-technologies, which you have to research via colleges, give you access to certain developments
-basic spawning garrisons are introduced, but very weak mainly
-capital is set, can't mbe moved, irrelevant to the game
-population growth depends on the taxation of the lower class mainly, techs and the set value; growth spawns new minor villages that you can develop to increase the region's wealth; every region has a set number of villages it can spawn, after which population growth is sort of irrelevant
Opinion: this worked really well as you could effectively manage your settlements according to your faction needs (economy, culture, religion) but also according to the importance of the settlement and its geographical position (in a choke point you'd rather build a military minor settlement than an economic one). Large settlements were also harder to control once captured, meaning that an eliminated top faction could respawn, effectively granting a balance between great factions and small ones in favour of the former and some sort of ''historical accuracy''.
Downsides:
-against the AI, the medium tier fort was easier to defend than the star fort in sieges (!)
-the AI in North America and India would not develop natural resources for some reason, or rarely. So when you conquered them, you'd find them undeveloped, despite the fact that the AI was making tons of money (hello Maratha)
Rating 9/10
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Shogun 2 TW:
-All settlements are now the same again.
-Very much like ETW, natural resources on the map can be interacted with and damaged by armies.
-introduction of the food dynamic: granaries and walls line now consume food, while farms produce it, requiring food surplus for the faction, otherwise you get starving armies and revolts
-given the above, for the first time in a TW game you actually don't want to develop your walls to the top level in every faction, because you won't have enough food to support it
-updgrading walls gives you an extra slot for buildings in the settlement
-streets require investment
-technology system further developed
-multiple buildings and unit slots per turn remains
-religion plays mostly the same as before
-basic garrisons are stronger, but that's mainly because the weakest units, the yari ashigaru, are actually pretty strong
-capital is set, can't mbe moved, irrelevant to the game
-growth concept is not present here either, technological research does it
Opinion: The two types system worked well in ETW but isn't missed nor needed in this one, as most factions start as ''equals''. The walls/food/slots system is great as it requires you to plan how you actually want to develop a settlement, if you want to leave it as a basic economic one, an economic powerhouse because it has high fertility or a specific rich economic resource, or a military one because it has some bonuses for troops. It gives great freedom to the player, though it can be complicated for newbyes.
Downsides:
-in many cases, you will finish the game's objectives before achieving top buildings, meaning you'll be missing out on a few top units
-you probably won't be able to create the ''perfect unit'' as in top weapons, charge, or accuracy, because settlements do not have that many slots you can fill with the required buildings to do it
Rating 9/10
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Rome 2 TW:
I think provinces were introduced because CA implemented a significantly larger map compared to Rome 1 (and did a great job with it).
-Every province has 2 to 4 settlements.
-The provincial capital has 5-6 buildings.
-Secondary settlements have 3-4.
-growth returns and allows you to add 1 building, up to the limits mentioned, every time you fullfill a level of growth required, tech is still present (so two elements influence how much you can expand your buildings)
-religion disappears (not needed, sort of irrelevant), cultural differences work as ''religion'' in terms of impact on public order
-there's no investment required for streets and walls, first time in the series (they develop with the rest of the settlement, but not individually), only the provincial capital has walls
-garrisons become stronger as you develop military buildings
-you can no longer interact with natural resources developed on the map
-capital is set, can't be moved, irrelevant to the game
-controlling all of the province grants various bonuses
-food system is further developed
-you can recruit units from settlements even if you are not in that region, but just in the province and they are automatically merged with the main army, which saves 1-3 turns every time you create an army;
Opinion: given the precedent experiences, it feels like what was a ''large settlement'' in ETW has been split in 3-4 ones, with the main one being a bit less relevant and what used to be just individual ''villages''/natural resources on the map being a bit more relevant. This is mainly due to the lack of walls of minor settlements.
In practice, it shouldn't change that much.
If I look at past games, the standard buildings for a secondary settlement that I would build mainly economically were:
-basic walls
-streets
-market
-farm
-public order building
-sometimes religious/cultural
Now the walls and streets upgrades disappear in Rome 2, so in the end it's again 3-4 buildings per settlement, it's actually the same as all the previous games. Yet it feels like the ''province'' is what used to be a single settlement, now split in 4. The map is huge, yet feels smaller in many areas. What used to take dozens of battles and tens of turns, like for example controlling the Middle East as the Seleucids, now can be achieved in.. 15. turns and 0 battles.
The lack of walls that many complained about has a massive impact. You can no longer decide your ''frontier'', the choke point you want to defend at. It's a massive conceptual error. You have massive freedom of choices for the other buildings, but it's all hampered by that limit and very much like M2TW, then the other relatively minor flaws build on that one.
It is accentuated by whether or not you own the full province, especially if you are playing a faction without bonuses that decrease the impact of the presence of other cultures.
Then stronger garrisons also make the AI over rely on them for defense. This creates a vicious circle:
-both the AI and the player will keep armies near or inside the settlement, not for the defenses (that it often lacks) but because settlements add some 5-6 garrison units in battles, often with a pair of decent quality units that can make the decisive difference; this is very noticeable on the autoresolve bar, where the addition of insignificant units regularly results in turning the tide an autoresolved battle
-this leads to a game of numbers, where the player will move 2 stacks to attack the same province, ensuring the numerical superiority instead of fighting the battles themselves and relying on tactical or strategical superiority
-the AI indeed either retaliates with further numbers, or by simply withdrawing, meaning your campaign from the mid game to the end will be the infamous ''walking from settlement to settlement''.
-additionally, there's a units imbalance: very much like M2TW were the imbalance of Italian militias sort of ruined the gameplay, here slingers do that. They are absolutely insane. The era of legions, cataphracts, pikes and elephants is dominated by.... slingers in both autoresolve and manual.
Now, the garrison problem, in theory is not the fault of the province system itself. We could have similar results in non-province systems with large spawning garrisons. However, just like other problems mentioned, it exacerbates already existing problems, namely the elimination of walls for secondary settlements, a notable flaw of the provincial system. Those two combined lead to the negative experience of gameplay: armies walking from settlement to settlement, very few field battles.
Additionally, the fast recruitment resulting from additional slots and automatic merging as long as they are created within the same province, not region, saves a lot of time, which makes the gameplay extremely fast.
Rating: 4/10
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Attila TW:
-religions replace cultures
-food system is developed even further; distribution is provincial and global;
-possibility to raze and abandon settlements
-large variety of buildings for various combinations
-top secondary settlement building adds walls to secondary settlements;
-every province is 3 settlements;
The changes compared to Rome 2, combined with the ''fluid'' gameplay of Attila and the migrations, hide some of the flaws of the provinces system.
The huge ramification of buildings combined with the 4-6 max building per settlement is a rather noticeable limitation. I'm all for shifting towards specialization, but the restrictions here are too heavy and some branches are clearly less useful than others. You'll never be using them, so it feels like they are there just to waste your time and attention.
The fact that food is not distributed not just globally, but provincially, forces you to shift away from specialization in a game that pushes you towards it. I think it's to limit the bonuses cumulating from specializating the province too much, but it further makes many building branches useless.
In the end, you have to make every province balanced in terms of food, public order, religion etc, which indeed feels like a province is a single settlement instead of 3.
If every province is, in the end, a single settlement, then the larger map results in an actually shrunk gameplay.
I don't have that much of experience to fully evaluate it for now. Might edit later.
I haven't played Warhammer but I heard the provinces system is still there. Is it better? When I look at the improvements made by CA from the mistakes in M2TW and the dual system (castle/cities) to the dual in ETW (Major/minor-economic, minor-military), I wonder, can the provinces systems be salvaged?