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

Execution · Competitive PvP
The Wii U Smash that restored competitive pace and a huge roster of labbable kill confirms.

Execution · Competitive PvP
A football sim testing stick control plus constant prediction of a human opponent's tactics.
Super Smash Bros. for Wii U leans Execution (Competitive PvP); World Soccer: Winning Eleven 9 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.
Super Smash Bros. for Wii U
Perfect pivots and precise aerial spacing reward sharp hands.
World Soccer: Winning Eleven 9
First-touch timing, dribbling and shot placement decide matches
Super Smash Bros. for Wii U leans a little harder on reads, though the gap is small.
Super Smash Bros. for Wii U
Ledge-trap and landing-trap guessing against humans never converges.
World Soccer: Winning Eleven 9
Human opponents feint, vary tactics and punish habits
World Soccer: Winning Eleven 9 leans a little harder on variance, though the gap is small.
Super Smash Bros. for Wii U
Tripping removed; only minor move RNG remains.
World Soccer: Winning Eleven 9
Deflections and referee calls add bounded chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Super Smash Bros. for Wii U
Rage mechanics and kill-confirm percents are deeply labbable.
World Soccer: Winning Eleven 9
Formations, player roles and set pieces reward study
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.