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 · Practiced Mastery
Timing-based grapple execution with light opponent prediction in multiplayer matches.

Execution · Competitive PvP
Reversal-timing duels where humans bait each other inside scripted spectacle.
WCW Mayhem leans Execution (Practiced Mastery); WWE SmackDown vs. Raw 2011 leans Execution (Competitive PvP).
WCW Mayhem leans a little harder on execution, though the gap is small.
WCW Mayhem
Timing grapples, reversals and strikes decides every match
WWE SmackDown vs. Raw 2011
Reversal timing windows reward practiced reactions
WWE SmackDown vs. Raw 2011 leans a little harder on reads, though the gap is small.
WCW Mayhem
Human opponents in versus add a modest prediction layer
WWE SmackDown vs. Raw 2011
Versus humans, reversal baiting becomes a guessing duel
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
WCW Mayhem
Weapon spawns and AI behaviour add minor noise
WWE SmackDown vs. Raw 2011
Momentum swings and AI quirks add mild chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
WCW Mayhem
Learning move lists and match-type quirks is a fixed problem
WWE SmackDown vs. Raw 2011
Move sets, match types and creation systems are learnable
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.