It is understandable that European civs share some architecture style because the “civ density” in Europe is quite dense in the game.
But I do think some “grand” “ultimate” buildings like forts and capitols (maybe even the town center) need to also have a unique style for each civ like the churches, based on some iconic buildings of the nations, to add more flavor.
Take cossacks for example. They have very iconic town centers for all civs:
Of course by AOE’s convention they should be standardized to a similar footprint. This is just a showcase. You could modify the main tower of the current AOE3 “standard town center” shape and also change the style of roofs, walls and windows, according to the civ’s iconic styles.
Also now that Europeans are no longer colonial exclusively, “capitol” sounds too American and maybe parliament is a better name for the building.
I had thought something similar, but with crops. If I’m not mistaken, all civilizations have cotton plantations or vineyards (I don’t know what it is exactly). Why not include sugar and coffee plantations for Spain and Portugal respectively?
All non-European civs (excluding post-colonial ones) have their own unique architecture. Asian civs also have 5 Wonders as their Age Up mechanic. Meanwhile, European civs only need to share three Architectural Sets with each other. In AoE 2, every civ has its own unique-looking Wonder building by default, and it’s possible that in the future every civ will get its own Castle model.
I think adding unique Capitol and Fort models to each European civ would be an eye-catcher. The old and boring models of these units could stay in the Scenario Editor and in Campaigns (as well as Historical Battles).
I will also add from myself that the huge October Update added a lot of unique units (including practically completely changed Ottomans). I think this proves that the creators are not afraid of reworks in vanilla civs that need novelty. That’s why I think a fourth “unique” resource could be added for European civs, which would be used even in the Capitol (which should be renamed to Parliament).