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

Execution · Practiced Mastery
Plannable stealth routing punctuated by precise ballistic marksmanship.

Execution · Practiced Mastery
Ballistic compensation and patrol memorisation along heavily scripted stealth corridors.
Sniper Elite III leans Execution (Practiced Mastery); Sniper: Ghost Warrior leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Ballistic long shots demand steady, compensated aim
Sniper: Ghost Warrior
Accounting for wind and drop on long shots demands steady aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Enemy AI follows mappable alert and search routines
Sniper: Ghost Warrior
Enemy AI runs scripted patrols, not adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Patrol details and wind vary slightly per attempt
Sniper: Ghost Warrior
Wind values add per-shot noise to compensate for
Sniper Elite III leans a little harder on optimization, though the gap is small.
Sniper Elite III
Open maps reward planned routes, sound masking and relocation
Sniper: Ghost Warrior
Learning patrol routes and stealth paths solves each level
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.