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

Execution · Competitive PvP
Classic fighting execution and human prediction atop a famously unbalanced roster.

Execution · Competitive PvP
The fourth Soulcalibur adds armor-breaking Soul Gauge pressure and Critical Finishes to its weapon dueling.
Mortal Kombat Trilogy leans Execution (Competitive PvP); Soulcalibur IV leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Dial-a-combo inputs and run-meter pressure demand fast hands
Soulcalibur IV
Step-guard and just-guard timing keep a real physical ceiling.
Soulcalibur IV leans a little harder on reads, though the gap is small.
Mortal Kombat Trilogy
Human opponents must be baited into unsafe moves
Soulcalibur IV
Critical Finish threats add layers to adaptive mixup guessing.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Movesets are public; nothing hidden in a match
Soulcalibur IV
Soul Gauge is visible; no hidden info.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Knowing the bloated roster's broken tech is half the battle
Soulcalibur IV
Guard-crush pressure routes and frame data are studyable.
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.