head to head
Warcraft III: Reign of Chaos asks more than StarCraft, and the gap is variance.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.
StarCraft leans Optimization (Grand Arena); Warcraft III: Reign of Chaos leans Optimization (Grand Arena).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
StarCraft
APM and micro control ceiling is huge
Warcraft III: Reign of Chaos
Micro of heroes and units decides fights
Warcraft III: Reign of Chaos leans a little harder on reads, though the gap is small.
StarCraft
scouting and predicting human opponent builds
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
Warcraft III: Reign of Chaos leans clearly harder on variance.
StarCraft
minimal hidden info beyond fog of war
Warcraft III: Reign of Chaos
Creep routes and item drops add randomness
StarCraft leans a little harder on optimization, though the gap is small.
StarCraft
build orders and economy are near-solvable
Warcraft III: Reign of Chaos
Build orders, creeping routes, and matchup theory run deep
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.