Using a deity as a Vancian spellbook just feels very undivine to me.
It all just depends on perspective. A D&D cleric based off a Catholic priest, would know most of the main prayers, but saying a prayer is not the same as casting a spell. Grace over dinner might have the same words as casting Purify Food and Drink, but at dinner the priest has no desire to call upon the overwhelming power of divinity.
The concept of the power of god(s) , being overwhelming and even dangerous to mortals is pretty common. This easily fits in with a Vancian system as being an explanation for spell levels and slots.
The corrupt local Bishop might appear less holy than the true faith of Joan Of Arc. in D&D terms, the Bishop is a Cleric 3/ Rogue 5 and Joan of Arc is Paladin 8
Likewise, the common trope of Exorcism style films, is prayers/rites that give the priest power over the possessed or undead is only known by a special few.....seems rather D&D-ish to me. The local vicar, does not know how to turn undead, or cast out ghosts from this world, but Jesuit order the player belongs to study those prayers.
Taste is solely one's own, but it might be a bit harsh given that, to write off universally for everyone the validity of a certain system, because it does met your own personal tastes.