head to head
Neither is simply harder - they are hard in different places. Guilty Gear Strive demands more execution; Warcraft III: Reign of Chaos demands more variance.

Execution · Grand Arena
A fast anime fighter where execution and yomi compound under pressure.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.
Guilty Gear Strive leans Execution (Grand Arena); Warcraft III: Reign of Chaos leans Optimization (Grand Arena).
Guilty Gear Strive leans clearly harder on execution.
Guilty Gear Strive
Tight links, RCs, and burst timing are demanding.
Warcraft III: Reign of Chaos
Micro of heroes and units decides fights
Guilty Gear Strive leans clearly harder on reads.
Guilty Gear Strive
Adaptive opponents bait Roman Cancels and throws.
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
Warcraft III: Reign of Chaos leans clearly harder on variance.
Guilty Gear Strive
Essentially deterministic match flow.
Warcraft III: Reign of Chaos
Creep routes and item drops add randomness
Warcraft III: Reign of Chaos leans clearly harder on optimization.
Guilty Gear Strive
Matchup data, combo routes, and tension management.
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.