Really cool ideas!
Holy Roman Empire (present Germans civ)
I think the current Germans civ should remain - it would change its name to Holy Roman Empire. Its Age Up would refer to the countries that were part of the HRE, e.g. Bavaria, Bohemia, Switzerland and Saxony (these changes would be visual and replace boring Politicians. These could be flags + emblems of these countries with the contours of their borders on the map - additionally they could contain a short description ). Uhlan would become the default Hussar replacement unit for Holy Roman Empire civ, Asutria-Hungary civ and Prussians civ. Royal Guards and HC cards would be renamed more HRE. The description of civ in the AoE 3 encyclopedia would be slightly updated. This civ would receive a new Home City (Prague, Akwirzgan, Nurnberg or Frankfurt) and a Ruler (Sigismund of Luxembourg). In this way, changes to this civ would not affect the entertainment, but would make it more attractive and historically correct.
Prussians
In my opinion your suggestions for Prussians civ are really interesting. Here are some of my suggestions:
Landwehr - it could be a replacement for Minuteman for Holy Roman Empire, Austria-Hungary and Prussians civs. Could have the stats you provided and would be grouped just like Minuteman. His disadvantage would be that he would lose half his HP after a minute.
Their Unique Units could be:
- Prussian Rifleman - your suggestion
- Silesian Schuetzen - Elite rifle-armed troops. They shoot from a long distance and deal massive damage at the cost of a very low rate of fire and training limit (only 10 such units at the same time)
- Teutonic Knight - Archaic heavy cavalry armed with a lance. Modeled on the Knights of the Order (Teutonic Knights and the Livonian Order). This unit would be the equivalent of the Elmeti.
Freikorps - voluntary, nationalist paramilitary formations operating in Germany in 1918–1922, founded by demobilized soldiers. So they don’t match in AoE 3.
It is too much. I think one building would be enough - Grube. It would be a building that would be built on a mine. Following the example of Mountain Monastery (a unique civ Ethiopian building), it would generate Coins or XP. Miners could be trained there. This building would have improvements such as: increasing the Coin abundance in Grube and increasing the number of trainable Miners. This building would contain a distinctive Headframe.
Austria-Hungary
In my opinion your proposals for Austria civ are much less attractive than Prussian civs.
You mentioned that Austro-Hungary was a multi-ethnic empire - that’s true. It is a pity that the units you specified focus only on two nations of this empire.
Landwehr - it could be a replacement for Minuteman for Holy Roman Empire, Austria-Hungary and Prussians civs. Could have the stats you provided and would be grouped just like Minuteman. His disadvantage would be that he would lose half his HP after a minute.
Their Unique Units could be:
- Hajduk - weak archer. They would use axe in hand-to-hand combat.
- Pandurs - ranged light gunpowder infantry. They would use Yatagan in hand-to-hand combat. This unit would be the equivalent of the Russian Unique Unit - Strelet
- Windbüchse Jäger
- Hungarian Hussar
Hungarian Rifleman and Hungarian Grenadier sound more like upgrades for the Skirmisher and the Granadier, respectively. I think the Hungarian revolution available to Austria-Hungary civ would cover it perfectly - additionally it has the Hungarian Hussar.
I think the Philharmonic would be more Austrian. But it still seems to me that such a building would not exist in AoE 3.
I propose a different building:
Festung (connection of the Barrack with the Stable. Unlike Fort and Blockhouse, it doesn’t defend. It has more than 2700 HP, but requires 350 wood and the construction time is 45 seconds).
I invite you to my topic about a potential European DLC. There are some of my suggestions for Austria-Hungary & Prussians - and more. You can also help me there, because I did not focus so much on unit statistics and Home City cards - and I see that you know how to make it interesting 