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
An anime fighter testing combo execution and counter-baiting against human opponents.

Execution · Competitive PvP
Fast anime fights where combo execution and reading a human rival decide rounds.
Dragon Ball Z: Budokai 3 leans Execution (Competitive PvP); Naruto: Ultimate Ninja 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.
Dragon Ball Z: Budokai 3
Combo execution, teleport counters and beam timing demand hands
Naruto: Ultimate Ninja 3
Combo timing and jutsu clashes reward quick hands
Dragon Ball Z: Budokai 3 leans a little harder on reads, though the gap is small.
Dragon Ball Z: Budokai 3
Versus humans, baiting teleports and guessing cancels decides exchanges
Naruto: Ultimate Ninja 3
Human versus play rewards baiting and habit punishing
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Budokai 3
Almost nothing random beyond minor clash inputs
Naruto: Ultimate Ninja 3
Fights are deterministic outside clash minigames
Dragon Ball Z: Budokai 3 leans a little harder on optimization, though the gap is small.
Dragon Ball Z: Budokai 3
Capsule builds and matchup knowledge underpin competitive play
Naruto: Ultimate Ninja 3
Character matchups and meter use are a thin learnable 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.