head to head
Neither is simply harder - they are hard in different places. Blood Bowl 2 demands more variance; Warcraft III: Reign of Chaos demands more execution.

Variance · Grand Arena
Turn-based fantasy football where orcs, elves, and dice decide the league.

Optimization · Grand Arena
Blizzard's hero-centric RTS where build-order theory meets surgical unit micro against humans.
Blood Bowl 2 leans Variance (Grand Arena); Warcraft III: Reign of Chaos leans Optimization (Grand Arena).
Warcraft III: Reign of Chaos leans clearly harder on execution.
Blood Bowl 2
Turn-based tactics; no reflex demand
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.
Blood Bowl 2
PvP positioning baits opponents into bad dice commitments
Warcraft III: Reign of Chaos
Scouting and out-guessing a human opponent's tech
Blood Bowl 2 leans clearly harder on variance.
Blood Bowl 2
Block dice and failed pickups decide entire matches
Warcraft III: Reign of Chaos
Creep routes and item drops add randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Blood Bowl 2
Risk-ordering actions and team development are deep solvable craft
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.