The old LLVs also have a slanted back, its possible its just for design, I'm picturing it with a flat back and it just looks wrong, like a typical creepy white

The old LLVs also have a slanted back, its possible its just for design, I'm picturing it with a flat back and it just looks wrong, like a typical creepy white van. The slope gives it some character. Although you're right, there probably is a more nuanced reason.