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.

Execution · Grand Arena
Chaotic tag fighter whose top tiers reward blistering execution and assist mastery.

Execution · Competitive PvP
Combo execution and endless mixup prediction against adapting human opponents.
Marvel vs. Capcom 2: New Age of Heroes leans Execution (Grand Arena); Persona 4 Arena leans Execution (Competitive PvP).
Marvel vs. Capcom 2: New Age of Heroes leans a little harder on execution, though the gap is small.
Marvel vs. Capcom 2: New Age of Heroes
infinite combos and assist timing demand elite hands
Persona 4 Arena
Combo execution and confirm timing gate competitive play
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom 2: New Age of Heroes
humans bait assists and mix high-low constantly
Persona 4 Arena
Mixups and throw-tech guessing against adapting humans never converge
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Marvel vs. Capcom 2: New Age of Heroes
fully deterministic engine
Persona 4 Arena
Almost nothing random in a fighting match
Marvel vs. Capcom 2: New Age of Heroes leans a little harder on optimization, though the gap is small.
Marvel vs. Capcom 2: New Age of Heroes
team order, assist synergy, and matchup knowledge
Persona 4 Arena
Frame data, matchup study and meter math reward homework
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.