Israel defined its God and its relation to that God in existential, relational terms. They did not, until quite late, approach the question of one God in an abstract philosophical way.
If I had to choose between the two ways of approaching the deity, I should prefer the existential relational way, to the abstract philosophical way. I think it is truer, or in any case, less misleading, to say that God is an old Jew with a white beard whom I love, than to say that God is the ground of being and meaning, or to say that God is a name denoting the ultimate mystery. I prefer the bold primitive colors of the Biblical way of describing God.
If one attempts to achieve deity or to have the holy, he is thrown back; he is refused. His language is taken from him. He can no longer even communicate. That's the Tower of Babel.
I do think that the Josianic return to the archaic form of the Passover is appropriate and, indeed, historical. Josiah does go back to a different, earlier tradition, the time of a central sanctuary in which the law code was read. But then there were accretions to the Book of Deuteronomy.
Furthermore, I think there was, in fact, a celebration of Passover in the era of the Judges in which the epic was recited in the context of the central sanctuary. That tradition was displaced by the Feast of Enthronement beginning in the Solomonic era.