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

Execution · Grand Arena
Sim-leaning combined-arms vehicle PvP.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.
War Thunder leans Execution (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.
War Thunder
Aim, lead, and vehicle handling demanding
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.
War Thunder
Position-versus-position duels are reads
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
War Thunder leans clearly harder on variance.
War Thunder
Shell ballistics and matchmaking vary
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.
War Thunder
Vehicle lineups and module unlocks deep
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.