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
Arcade baseball testing hit timing and pitch prediction in versus play.

Execution · Competitive PvP
Arena fighting built on baiting substitutions and timing punishes against humans.
Mario Superstar Baseball leans Execution (Competitive PvP); Naruto Shippuden: Ultimate Ninja Storm 3 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.
Mario Superstar Baseball
Bat timing and charged pitches are the core motor test
Naruto Shippuden: Ultimate Ninja Storm 3
Substitution timing and combo confirms need decent hands
Naruto Shippuden: Ultimate Ninja Storm 3 leans a little harder on reads, though the gap is small.
Mario Superstar Baseball
Guessing a human pitcher's mix is the versus layer
Naruto Shippuden: Ultimate Ninja Storm 3
PvP revolves around baiting substitutions from human opponents
Mario Superstar Baseball leans a little harder on variance, though the gap is small.
Mario Superstar Baseball
Star swings and bobbles add bounded randomness
Naruto Shippuden: Ultimate Ninja Storm 3
Support meter and item randomness barely matter
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Superstar Baseball
Chemistry pairings and lineups are quickly learned
Naruto Shippuden: Ultimate Ninja Storm 3
Team composition and awakening knowledge add a thin layer
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.