head to head
Call of Duty: Modern Warfare 2 asks more than FIFA: Road to World Cup 98, and the gap is execution.

Execution · Competitive PvP
Blockbuster 2009 sequel famous for killstreak chains and frantic multiplayer.

Execution · Competitive PvP
Fast arcade football execution with couch-multiplayer mind games.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); FIFA: Road to World Cup 98 leans Execution (Competitive PvP).
Call of Duty: Modern Warfare 2 leans clearly harder on execution.
Call of Duty: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
FIFA: Road to World Cup 98
Arcade-paced dribbling and shot timing decide matches
Call of Duty: Modern Warfare 2 leans clearly harder on reads.
Call of Duty: Modern Warfare 2
Outguessing human rotations and flanks
FIFA: Road to World Cup 98
Couch opponents can be baited; AI cannot
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
FIFA: Road to World Cup 98
Bouncy ball physics inject classic FIFA luck
Call of Duty: Modern Warfare 2 leans clearly harder on optimization.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
FIFA: Road to World Cup 98
Simple era tactics and exploit goals are quickly mapped
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.