It is certainly possible with relatively little programming effort to add small but actually important details into the environment that make the whole game more lively:
-Chickens in the village center could move around a bit
-Horses in the building stable could move their tails
-Arrows that hit after a unit has been killed may get stuck in the ground
-Corpses could slowly disappear into the ground
-Reload animation on each siege unit with these “ghost silhouettes”
-Wild animals that match the different biomes
-Units in siege mode could visibly carry their weapons sheathed on their backs or similar as is the case in AoE 3
-footprints/wheel tracks
in snow and sand
-The self-made banner could blow small but still visible in the wind on important buildings such as the village center