head to head
Neither is simply harder - they are hard in different places. Age of History III demands more reads; The Elder Scrolls V: Skyrim demands more execution.

Optimization · Pure Optimization
A grand strategy wargame about economy, diplomacy, and conquest across history.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
Age of History III leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
Age of History III
Map clicks need no timing or twitch
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
Age of History III leans clearly harder on reads.
Age of History III
AI nations follow doctrine; humans can adapt
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
Age of History III leans a little harder on variance, though the gap is small.
Age of History III
Battle outcomes and events add some chance
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Age of History III leans a little harder on optimization, though the gap is small.
Age of History III
Economy, diplomacy and conquest planning are the whole game
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits are deeply solvable.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.