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

Optimization · Pure Optimization
Optimizing city placement, social policies, and victory routing under randomized map unknowns.

Optimization · Pure Optimization
Specializing magical cities and unlocking spells to dominate a randomly generated arcane world.
Civilization V leans Optimization (Pure Optimization); Warlock: Master of the Arcane leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
UI actions need no precision; speed is not a factor
Warlock: Master of the Arcane
Fully turn-based hex strategy; no physical precision ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
AI follows scripted personalities, not genuine player modelling
Warlock: Master of the Arcane
AI lords use scripted expand-and-attack patterns without real modelling
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
Random starts, barbarian spawns, and goody huts create hidden unknowns
Warlock: Master of the Arcane
Random spell research results and dungeon encounters add genuine unknowns
Civilization V leans a little harder on optimization, though the gap is small.
Civilization V
Hex placement, social policies, and victory routing are fully solvable
Warlock: Master of the Arcane
City specialization and spell unlocking form the dominant solvable layer
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.