head to head
Warhammer 40,000: Dawn of War II asks more than Natural Selection 2, and the gap is variance.

Execution · Grand Arena
Asymmetric FPS-RTS hybrid where aliens and marines fight under live human commanders.

Execution · Grand Arena
Hero-driven squad RTS where wargear optimization and ability timing combine with reading aggressive opponents.
Natural Selection 2 leans Execution (Grand Arena); Warhammer 40,000: Dawn of War II leans Execution (Grand Arena).
Natural Selection 2 leans a little harder on execution, though the gap is small.
Natural Selection 2
Skulk movement and marine aim have steep ceilings
Warhammer 40,000: Dawn of War II
Hero ability activation and squad retreat timing are mechanically demanding
Warhammer 40,000: Dawn of War II leans a little harder on reads, though the gap is small.
Natural Selection 2
Human commanders mind-game tech and map control
Warhammer 40,000: Dawn of War II
Opponent army composition and hero focus must be predicted
Warhammer 40,000: Dawn of War II leans clearly harder on variance.
Natural Selection 2
Symmetric maps, little randomness
Warhammer 40,000: Dawn of War II
Retreat damage, wargear drops, and map control variance add uncertainty
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Natural Selection 2
Tech trees, res flow, and lifeform timings
Warhammer 40,000: Dawn of War II
Wargear builds and ability upgrade sequences are optimizable
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.