head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Competitive PvP
Weapon-based dueling testing spacing execution and mixup prediction against humans.

Execution · Competitive PvP
The Wii U Smash that restored competitive pace and a huge roster of labbable kill confirms.
SoulCalibur III leans Execution (Competitive PvP); Super Smash Bros. for Wii U leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
SoulCalibur III
Spacing, movement and just-frame timing demand real hands
Super Smash Bros. for Wii U
Perfect pivots and precise aerial spacing reward sharp hands.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
SoulCalibur III
Versus humans, conditioning and throw-mixup guessing decides rounds
Super Smash Bros. for Wii U
Ledge-trap and landing-trap guessing against humans never converges.
Super Smash Bros. for Wii U leans a little harder on variance, though the gap is small.
SoulCalibur III
Deterministic combat with nothing hidden
Super Smash Bros. for Wii U
Tripping removed; only minor move RNG remains.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
SoulCalibur III
Frame data, matchup study and stage knowledge run deep
Super Smash Bros. for Wii U
Rage mechanics and kill-confirm percents are deeply labbable.
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.