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
The original 2003 WWII shooter built around cinematic squad set pieces.

Execution · Practiced Mastery
Timing-based grapple execution with light opponent prediction in multiplayer matches.
Call of Duty leans Execution (Practiced Mastery); WCW Mayhem leans Execution (Practiced Mastery).
Call of Duty leans a little harder on execution, though the gap is small.
Call of Duty
Aim and reaction carry the scripted firefights
WCW Mayhem
Timing grapples, reversals and strikes decides every match
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty
Light multiplayer prediction; campaign AI is scripted
WCW Mayhem
Human opponents in versus add a modest prediction layer
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty
Some spawn and hit unpredictability
WCW Mayhem
Weapon spawns and AI behaviour add minor noise
Call of Duty leans a little harder on optimization, though the gap is small.
Call of Duty
Memorising set pieces and weapon positions
WCW Mayhem
Learning move lists and match-type quirks is a fixed problem
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.