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 · Competitive PvP
Shot timing and play selection against opponents adjusting to your tendencies.

Execution · Competitive PvP
A basketball sim testing stick execution and reading opponents on court.
NBA 2K14 leans Execution (Competitive PvP); NBA 2K6 leans Execution (Competitive PvP).
NBA 2K6 leans a little harder on execution, though the gap is small.
NBA 2K14
Shot release timing and dribble chains gate scoring
NBA 2K6
Stick skills, timing shots and dribbling carry play
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
NBA 2K14
Online opponents counter your favourite plays
NBA 2K6
Human opponents online require reading and faking
NBA 2K6 leans a little harder on variance, though the gap is small.
NBA 2K14
Shot RNG sways close possessions
NBA 2K6
Shot success and AI have some randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
NBA 2K14
Playbook knowledge and roster management reward study
NBA 2K6
Play calling, roster and matchup management matter
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.