head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Competitive PvP
A team arena brawler testing loose execution and squad composition over precision.

Execution · Competitive PvP
Substitution baiting against humans atop simple anime-fighter inputs and team picks.
Dragon Ball Z: Battle of Z leans Execution (Competitive PvP); Naruto Shippuden: Ultimate Ninja Storm 2 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: Battle of Z
Aerial chases and ki timing need moderate hands
Naruto Shippuden: Ultimate Ninja Storm 2
Timing substitutions and combos matters but inputs are simple
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Battle of Z
Team fights against humans involve loose target prediction
Naruto Shippuden: Ultimate Ninja Storm 2
Versus humans, baiting substitutions is the real layer
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Battle of Z
Little hidden beyond card drops for builds
Naruto Shippuden: Ultimate Ninja Storm 2
Nothing hidden once both characters are known
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Battle of Z
Team synergy cards and role composition are the system layer
Naruto Shippuden: Ultimate Ninja Storm 2
Team composition and chakra management have solvable lines
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.