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

Execution · Practiced Mastery
Planning a kill order and landing extreme-range ballistic shots against scripted patrols.
Sniper Elite III leans Execution (Practiced Mastery); Sniper Ghost Warrior Contracts 2 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 Contracts 2
Aimbot trivialises the long-range ballistic shots that define it
Sniper Elite III leans a little harder on reads, though the gap is small.
Sniper Elite III
Enemy AI follows mappable alert and search routines
Sniper Ghost Warrior Contracts 2
Enemy patrols follow fixed scripts, never adapting to your tactics
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 Contracts 2
Wind and patrol layouts are unknown until scouted, then fixed
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Open maps reward planned routes, sound masking and relocation
Sniper Ghost Warrior Contracts 2
Planning routes, shot order and contract objectives is half the game
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.