My main issue with the cleric is it doesn't bring any real connection to the church or religious organization the cleric as a part of, and that in theory is one of the main story cruxes of the cleric.
I agree that something like the celestial warlock much better represents the "person chosen by a deity to act in the world under their name", sort of an avatar like concept. divine soul sorcerers handle the "innate divine power or blood" concept.
To me what makes the cleric the cleric is the church. They are its representative, its enforcer, its PR campaigner, or maybe even a church leader. None of that is really brought in to the class, and I think the archetype is diminished before of it.