head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Variance · Grand Arena
A digital card game balancing opponent reads against draw variance.

Optimization · Grand Arena
Territory math and dice management entangled with reading human alliances.
Hearthstone leans Variance (Grand Arena); Risk: Global Domination leans Optimization (Grand Arena).
Hearthstone leans a little harder on execution, though the gap is small.
Hearthstone
Clicks only, no mechanical skill
Risk: Global Domination
Clicking territories takes no physical skill
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hearthstone
Human opponents bluff and adapt mid-match
Risk: Global Domination
Human diplomacy, truces and betrayal timing cannot be solved
Hearthstone leans a little harder on variance, though the gap is small.
Hearthstone
Draw RNG and discover effects swing games
Risk: Global Domination
Dice rolls swing battles and mission cards hide information
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Hearthstone
Deckbuilding, mulligans, and mana curves matter
Risk: Global Domination
Continent bonuses, troop math and border control are calculable
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.