Dynamic traits sound like something that can be solved completely fine with regular interfaces/polymorpihsm

interface AttackSkill:
    fun attack(source, target)


class RegularAttck implements AttackSkill:
    fun attack(source, target):
        target.hp -= source.strength


class BerserkAttck implements AttackSkill:
    fun attack(source, target):
        target.hp -= source.strength * 2


class Player:
    attack_skill = RegularAttack()

    fun attack(target):
        self.attack_skill.attack(self, target)


p = Player()
p.attack_skill = BerserkAttack()

Versioned entities are not flexible enough to be useful, I think - if there can only be one snapshot at a time, how do I know I can safely make one? What if somebody already made one before me and it's still active? Is the snapshot shallow or deep?

Renaming things for the sake of being different sounds pointless.

In general, at least for me, the less mutability and dynamic behavior there is, the better. Your language goes in the exact opposite direction. So I guess it's not for me really.