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
A shallow novelty wrestler testing little beyond basic timing and weapon grabs.

Execution · Competitive PvP
Reversal timing and pacing against an opponent baiting your counters.
Celebrity Deathmatch 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.
Celebrity Deathmatch
Button timing wins matches but the ceiling is low
WWE 2K15
Reversal timing windows decide most exchanges
WWE 2K15 leans a little harder on reads, though the gap is small.
Celebrity Deathmatch
A couch opponent can be conditioned, shallowly
WWE 2K15
Human opponents bait reversals and vary move timing
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Celebrity Deathmatch
Random weapon drops shake up the ring
WWE 2K15
Chain-wrestling rock-paper-scissors minigames add randomness
WWE 2K15 leans a little harder on optimization, though the gap is small.
Celebrity Deathmatch
Learning each celebrity's finisher exhausts the depth fast
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.