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

Optimization · Grand Arena
Territory math and dice management entangled with reading human alliances.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.
Risk: Global Domination leans Optimization (Grand Arena); Warcraft III: Reign of Chaos leans Optimization (Grand Arena).
Warcraft III: Reign of Chaos leans clearly harder on execution.
Risk: Global Domination
Clicking territories takes no physical skill
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.
Risk: Global Domination
Human diplomacy, truces and betrayal timing cannot be solved
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
Risk: Global Domination leans clearly harder on variance.
Risk: Global Domination
Dice rolls swing battles and mission cards hide information
Warcraft III: Reign of Chaos
Creep routes and item drops add randomness
Warcraft III: Reign of Chaos leans a little harder on optimization, though the gap is small.
Risk: Global Domination
Continent bonuses, troop math and border control are calculable
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.