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
A 3rd Edition ruleset combat puzzle where multi-classing and feat selection unlock dominant strategies.

Optimization · Pure Optimization
An original RPG system where engagement optimization and passive-stacking theory dominate hard-mode encounters.
Icewind Dale II leans Optimization (Pure Optimization); Pillars of Eternity 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.
Icewind Dale II
Real-time-with-pause negates twitch requirements
Pillars of Eternity
Real-time-with-pause removes all twitch pressure from the player
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Icewind Dale II
Scripted enemy routines offer nothing to read or predict adaptively
Pillars of Eternity
All AI opponents use fixed scripted behaviour trees
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Icewind Dale II
3E feat combinations and hidden enemy resistances create unknown-information layers
Pillars of Eternity
Hidden enemy immunities and ability distributions require investigation
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Icewind Dale II
3rd Edition feat optimization and multi-class architecture dominate success
Pillars of Eternity
Per-encounter ability management and passive stacking define trial-of-iron mastery
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.