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
Stick-skill football execution with opponent prediction in versus play.
NBA 2K16 leans Execution (Competitive PvP); UEFA Euro 2008 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
UEFA Euro 2008
Pass timing, dribbling and finishing decide matches
NBA 2K16 leans a little harder on reads, though the gap is small.
NBA 2K16
Online opponents adjust defensive schemes against your tendencies
UEFA Euro 2008
Versus humans, baiting tackles and disguising attacks matters
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
NBA 2K16
Shot RNG and card packs add bounded randomness
UEFA Euro 2008
Bounces and deflections add football's usual noise
NBA 2K16 leans a little harder on optimization, though the gap is small.
NBA 2K16
Playbooks, rotations and roster building reward deep study
UEFA Euro 2008
Formations and squad selection sit underneath
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.