head to head
Neither is simply harder - they are hard in different places. StarCraft demands more optimization; Warhammer 40,000: Dawn of War demands more variance.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.

Reads · Grand Arena
Grimdark RTS where requisition nodes, squad reinforcement, and chapter counter-picks define competitive depth.
StarCraft leans Optimization (Grand Arena); Warhammer 40,000: Dawn of War leans Reads (Grand Arena).
StarCraft leans a little harder on execution, though the gap is small.
StarCraft
APM and micro control ceiling is huge
Warhammer 40,000: Dawn of War
Squad retreat timing and builder unit micro require practiced hands
Warhammer 40,000: Dawn of War leans a little harder on reads, though the gap is small.
StarCraft
scouting and predicting human opponent builds
Warhammer 40,000: Dawn of War
Opponent chapter choice and rush timing must be predicted
Warhammer 40,000: Dawn of War leans clearly harder on variance.
StarCraft
minimal hidden info beyond fog of war
Warhammer 40,000: Dawn of War
Relic capture variance and squad reinforcement timing add uncertainty
StarCraft leans clearly harder on optimization.
StarCraft
build orders and economy are near-solvable
Warhammer 40,000: Dawn of War
Requisition node priority and tech tree builds are well-studied
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.