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.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Optimization · Practiced Mastery
San Francisco hacker sandbox blending stealth, drones, and toy gadgets.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Watch Dogs 2 leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Watch Dogs 2
Shooting and driving moderate input demands.
Watch Dogs 2 leans a little harder on reads, though the gap is small.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Watch Dogs 2
Enemy AI scripted; some PvP invasions exist.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Watch Dogs 2
Hack outcomes and patrols vary mildly.
Grand Theft Auto: San Andreas leans a little harder on optimization, though the gap is small.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Watch Dogs 2
Gadgets, hacks, mission approaches solvable.
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.