head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
Fantasy 4X with strong asymmetric factions and quest paths.

Optimization · Pure Optimization
Classical 4X with dynastic events and order economy.
Endless Legend leans Optimization (Pure Optimization); Old World leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Endless Legend
turn-based
Old World
turn-based, no twitch
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Endless Legend
scripted AI, limited MP
Old World
AI scripted, some MP
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Endless Legend
quest and tech rolls
Old World
event cards, character traits
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Endless Legend
faction-specific yield optimization
Old World
orders, families, tech routing
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.