head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Practiced Mastery
A football sim testing play execution and play-calling prediction against opponents.

Execution · Competitive PvP
Shot timing and play selection against opponents adjusting to your tendencies.
Madden Football 64 leans Execution (Practiced Mastery); NBA 2K14 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.
Madden Football 64
Throw and run timing decides plays in real time
NBA 2K14
Shot release timing and dribble chains gate scoring
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Madden Football 64
Human opponents disguise plays, demanding prediction
NBA 2K14
Online opponents counter your favourite plays
Madden Football 64 leans a little harder on variance, though the gap is small.
Madden Football 64
Catch and fumble outcomes carry simulated randomness
NBA 2K14
Shot RNG sways close possessions
Madden Football 64 leans a little harder on optimization, though the gap is small.
Madden Football 64
Playbook, audibles and roster tactics run deep
NBA 2K14
Playbook knowledge and roster management reward study
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.