I’m talking about a time frame shifted slightly earlier than AOE3. Roughly 1400s to 1700s.
The only problem I have with AOE3 is that it covers most of the period but poorly represented it. The game is more focus on 1700s and later (musketeers that start with bayonets, hussars as standard European cavalry in the early game). In the meantime obsolete weapons like bows can compete with (on many occasions outperform) gunpowder. This is understandable for a game design, but it would be a pity to omit this very interesting time period.
So I think it’s a good idea to shift the core time frame a little earlier. And here are my reasons:
Great varieties in the weaponry
Gunpowders are taking over, but traditional cold steel weapons still see some use. This period features combination of firearms and melee weapons, and huge differences across the regions. In other parts of the world, horse archery is still useful around the steppes. Native Americans have their obsidian or hardwood weapons.
This would not create the oddity of bows or javelins beating rifles, because the latter is still in a rather primitive stage.
Global conflicts of civilizations
This is the first time where far ends of the globe meet, and none have yet to gain the dominance. Western Europeans were exploring the new world while waging religious wars on each other. Eastern Europe was chaotic and violent with the time of troubles and the deluge. Islamic Empires were expanding. Ming China was on constant conflicts with its neighbors. Japan was under the Sengoku period. There were fierce conflicts of arms and ideas.
Almost a century later, many native American civilizations were conquered. China and Japan started isolation and saw a period of relative peace. The great Islamic “gunpowder empires” were on steady decline.
Awesome armour, and many other popular cultural images
The typical “full plate armour knight” image was not actually a medieval thing but came with the advent of gunpowder. Armour design and production peaked in the late Renaissance.
One problem with the setting of AOE3 is the difficulty placing armoured units. In reality soldiers gradually discarded their armour during this time, but it looks odd if a unit loses armour with upgrades in a game. Also it is difficult to portray a “more armoured but less effective” unit in an RTS.
However if the focus is late Renaissance and Thirty Years War, heavily armoured lancers still could have a place in the mid-late game. And the awesome-looking, pistol-wielding cuirassiers could be the late game “high tech” unit.
Furthermore, many other popular cultural images, like the typical samurai, also emerge in this period.
So my envisioning of the tech tree is as follows:
Age 1: the typical “early game” with minimal military, maybe only pikemen, archers (bows or crossbows, depending on the region) and scouts.
Age 2: the “transitional stage”. Early gunpowder weapons like arquebuses emerge, along with general-purpose heavy melee infantry (with swords or halberds) and light cavalry.
Age 3: like every AOE game, the stage with true “full military”. This age features advanced firearms (muskets), heavy cavalry, ranged cavalry and of course artillery pieces.
Age 4: the “late game” with improved units from the previous age and some more “high tech” units like grenadiers, cuirassiers and more advanced artillery