head to head
Neither is simply harder - they are hard in different places. Warcraft III: Reign of Chaos demands more execution; Yu-Gi-Oh! Duel Links demands more variance.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.

Optimization · Grand Arena
A fast-format digital Yu-Gi-Oh! card game built around ranked PvP and meta decks.
Warcraft III: Reign of Chaos leans Optimization (Grand Arena); Yu-Gi-Oh! Duel Links leans Optimization (Grand Arena).
Warcraft III: Reign of Chaos leans clearly harder on execution.
Warcraft III: Reign of Chaos
Micro of heroes and units decides fights
Yu-Gi-Oh! Duel Links
Tapping cards, no dexterity test
Warcraft III: Reign of Chaos leans a little harder on reads, though the gap is small.
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
Yu-Gi-Oh! Duel Links
Ranked PvP rewards predicting set cards and bluffs
Yu-Gi-Oh! Duel Links leans clearly harder on variance.
Warcraft III: Reign of Chaos
Creep routes and item drops add randomness
Yu-Gi-Oh! Duel Links
Draws and unknown opponent decks dominate
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Warcraft III: Reign of Chaos
Build orders, creeping routes, and matchup theory run deep
Yu-Gi-Oh! Duel Links
Meta deckbuilding and line calculation are the spine
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.