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

Execution · Competitive PvP
Arena fighting built on baiting substitutions and timing punishes against humans.

Execution · Competitive PvP
A grapple-timing and guessing game built for couch competition.
Naruto Shippuden: Ultimate Ninja Storm 3 leans Execution (Competitive PvP); WWF WrestleMania 2000 leans Execution (Competitive PvP).
WWF WrestleMania 2000 leans a little harder on execution, though the gap is small.
Naruto Shippuden: Ultimate Ninja Storm 3
Substitution timing and combo confirms need decent hands
WWF WrestleMania 2000
Grapple timing and reversal windows reward fast hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Naruto Shippuden: Ultimate Ninja Storm 3
PvP revolves around baiting substitutions from human opponents
WWF WrestleMania 2000
Versus friends, grapple-versus-strike guessing is a real mind game
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Naruto Shippuden: Ultimate Ninja Storm 3
Support meter and item randomness barely matter
WWF WrestleMania 2000
Momentum swings add some scripted drama
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Naruto Shippuden: Ultimate Ninja Storm 3
Team composition and awakening knowledge add a thin layer
WWF WrestleMania 2000
Move sets and reversal systems are learnable but shallow
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.