P3 protag is OG. Jinjuriki of Death. Canonically maxes every social link. Unlocks Universe Arcana. Achieves answer to life. Can summon two personas at the same time (fusion spells). Has four personal personas (Orpheus, Orpheus Telos, Thanatos, Messiah).
And, I dunno, I feel like P5 hero would get a slight upper hand versus P4 hero. Probably the whole gun and physical enhancements with the costumes thing.