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 arena fighter testing team-switch timing and counter prediction against humans.

Execution · Competitive PvP
Reversal timing and pacing against an opponent baiting your counters.
One Piece: Burning Blood leans Execution (Competitive PvP); WWE 2K15 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.
One Piece: Burning Blood
Combo timing and guard breaks need moderate hands
WWE 2K15
Reversal timing windows decide most exchanges
One Piece: Burning Blood leans a little harder on reads, though the gap is small.
One Piece: Burning Blood
Human opponents bait switches and counters constantly
WWE 2K15
Human opponents bait reversals and vary move timing
WWE 2K15 leans a little harder on variance, though the gap is small.
One Piece: Burning Blood
Full-information arena with no hidden state
WWE 2K15
Chain-wrestling rock-paper-scissors minigames add randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
One Piece: Burning Blood
Team composition and Devil Fruit matchups reward study
WWE 2K15
Move sets, stamina and match pacing are learnable systems
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.