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
Slow-motion gunfights against aggressive but ultimately mappable squad AI.

Execution · Pure Mechanics
Motion-controlled tennis, bowling, golf, baseball and boxing built around simple swing gestures.
F.E.A.R. 3 leans Execution (Practiced Mastery); Wii Sports leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
F.E.A.R. 3
Slow-mo gunplay still rewards fast accurate aim
Wii Sports
Motion swing timing and accuracy decide every event
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
F.E.A.R. 3
Squad AI flanks convincingly but follows mappable routines
Wii Sports
Casual local opponents add light mind games
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
F.E.A.R. 3
Encounter layouts are scripted-but-unknown first time
Wii Sports
Minor physics wobble and CPU behaviour randomness
F.E.A.R. 3 leans a little harder on optimization, though the gap is small.
F.E.A.R. 3
Cover usage and power timing are quickly learned
Wii Sports
Simple technique tricks like bowling spin are learnable
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.