H is for: Heaven and hell, a discussion of fictional honesty

There is a certain supernatural novel I read recently. In it, fallen angels are handsome, dangerous boys who happen to be close to the MC's age. They're immature, full of conceit and irony, and for some inexplicable reason, make the MC almost pant with yearning despite the fact the one she likes blows so hot and cold, she'd have more success using a hair dryer inside a freezer.

Then there is the tale of a girl angel, bound to protect a certain handsome human. She, of course, falls in love and is caught  in a snare of her own emotions. He is mortal, she's got a hot-demon rival for her love and however will they make it work? Especially in fifty years when she's the same age and he's an old geezer...

Basically, these stories are romance novels. The angels and demons don't behave like their namesakes- which aren't human, can't reproduce and have a specific, limited purpose on Earth if one reads the Judeo-Christian stories. The authors lifted certain elements in these stories out of context - while still relying on readers' understanding of those traditions - yet substitute in no new rules for the ones they discard. In these stories, an angel is simply a girl with wings who lives a really long time. A demon is a misunderstood young man who, inspired by his pure love for a girl, fights against his twisted nature.

Now, I have no problem with either of these character types. What I question is their titles. Let's say I want to write a book about animals and my MC is a raccoon. We all know what a raccoon looks like, right? Striped fuzzy tail, cute little hands, a mask around its eyes, can hiss like a cat. In my story, I don't have to waste words describing this animal  because almost everyone has seen one and knows how it behaves just from reading its title. This is called prior knowledge.

But I've decided that my raccoon doesn't have a tail. In fact, it has wings. And four sets of hands. And its fur shoots lightning. It still has a mask around its eyes, though, but instead of scavenging for garbage and living in attics, my raccoons rule the world.

Right there, I took your prior knowledge and stamped it to pieces. I've manipulated the concept of a raccoon beyond all recognition. So why did I insist on calling my MC a raccoon? Why not just call it a ransflog? Or a coopcat?

Authors like Tamora Pierce, Juliet Marillier and Frank Peretti build their worlds from almost whole cloth. Marillier weaves her settings around Druidic tradition while Peretti stays true to the Christian idea of angels and demons battling it out in unseen realms. And Pierce pulls an entire world's mythology straight from her imagination. All these writers stay consistent to the rules of their chosen tradition - whatever they are - drawing the reader into a satisfying conclusion. They don't need a bait-and-switch to keep you hooked.

So what do you think? Is it possible for an author to be lazy in their worldbuilding? Or should anything go in fiction?