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

Execution · Competitive PvP
Shot timing and play-calling against opponents who scheme around your habits.

Execution · Competitive PvP
An American football sim mixing stick execution with play-calling mind games versus opponents.
NBA 2K16 leans Execution (Competitive PvP); NFL 2K3 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.
NBA 2K16
Shot-stick timing and dribble moves gate every possession
NFL 2K3
Stick control of players demands timing and reaction
NFL 2K3 leans a little harder on reads, though the gap is small.
NBA 2K16
Online opponents adjust defensive schemes against your tendencies
NFL 2K3
Play-calling against human opponents is constant prediction
NFL 2K3 leans a little harder on variance, though the gap is small.
NBA 2K16
Shot RNG and card packs add bounded randomness
NFL 2K3
Fumbles and bounces inject randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
NBA 2K16
Playbooks, rotations and roster building reward deep study
NFL 2K3
Playbook knowledge and matchups 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.