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.

Reads · Mind & Math
Objective-driven MOBA with shared team XP.

Optimization · Grand Arena
Large-scale RTS testing economic optimization, multitask speed and prediction of human build choices.
Heroes of the Storm leans Reads (Mind & Math); Supreme Commander 2 leans Optimization (Grand Arena).
Supreme Commander 2 leans a little harder on execution, though the gap is small.
Heroes of the Storm
Skillshots and rotations require hands
Supreme Commander 2
Macro APM across huge armies separates skirmish winners
Heroes of the Storm leans a little harder on reads, though the gap is small.
Heroes of the Storm
Team-fight cooldown trading is prediction
Supreme Commander 2
Multiplayer rewards scouting and predicting a human's tech switches
Heroes of the Storm leans a little harder on variance, though the gap is small.
Heroes of the Storm
Map objectives and merc camps vary
Supreme Commander 2
Open maps leave little hidden beyond fog of war
Supreme Commander 2 leans a little harder on optimization, though the gap is small.
Heroes of the Storm
Talent picks and team comps deep
Supreme Commander 2
Economy ratios, build orders and research routing are deeply solvable
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.