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 sequel adding Horde mode to the campaign-plus-versus cover shooter formula.

Execution · Competitive PvP
Simulation-styled WWE entry praised for its showcase mode and refined reversal-based combat.
Gears of War 2 leans Execution (Practiced Mastery); WWE 2K19 leans Execution (Competitive PvP).
Gears of War 2 leans a little harder on execution, though the gap is small.
Gears of War 2
Gnasher battles and movement tech set the ceiling
WWE 2K19
Reversal timing windows and combo execution
WWE 2K19 leans a little harder on reads, though the gap is small.
Gears of War 2
Human opponents in versus drive prediction play
WWE 2K19
Human versus matches hinge on counter prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War 2
Horde spawns add mild randomness
WWE 2K19
Slight randomness in pin kick-outs and AI
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Gears of War 2
Power-weapon timing and positioning are solvable
WWE 2K19
Payback systems, move-set knowledge and MyPlayer builds
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.