head to head
Diablo III asks more than Vagrant Story, and the gap is variance.

Optimization · Pure Optimization
A pure loot-and-build treadmill where set-bonus optimisation and Rift pushing define performance.

Optimization · Pure Optimization
A dense action RPG where mastering weapon affinity crafting and risk-chain mechanics against fixed enemies is the game.
Diablo III leans Optimization (Pure Optimization); Vagrant Story leans Optimization (Pure Optimization).
Vagrant Story leans a little harder on execution, though the gap is small.
Diablo III
Greater Rift pushing has minor mechanical demand in builds
Vagrant Story
Break Arts timing and chain management require active engagement
Diablo III leans a little harder on reads, though the gap is small.
Diablo III
No meaningful adaptive opponent; co-op is cooperative
Vagrant Story
All enemies and bosses follow fixed AI scripts
Diablo III leans clearly harder on variance.
Diablo III
Primal Ancient drops and set dungeon RNG drive the grind
Vagrant Story
Affinity system has some randomness in chain outcomes
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Diablo III
Set bonuses and paragon levelling are almost entirely solvable
Vagrant Story
Weapon crafting, risk management, and affinity stacking are the dominant system
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.