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
A basic arcade soccer game testing input timing and simple positioning.

Execution · Competitive PvP
Reversal timing and pacing against an opponent baiting your counters.
Champions World Class Soccer leans Execution (Practiced Mastery); WWE 2K15 leans Execution (Competitive PvP).
Champions World Class Soccer leans a little harder on execution, though the gap is small.
Champions World Class Soccer
Passing, shooting and tackling timing carry every play
WWE 2K15
Reversal timing windows decide most exchanges
WWE 2K15 leans a little harder on reads, though the gap is small.
Champions World Class Soccer
Two-player mode lets you predict a human opponent
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.
Champions World Class Soccer
Little randomness once team ratings are known
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.
Champions World Class Soccer
Formation choice and team selection give a known edge
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.