Bold assertion: It can be a sign of dangerous intellectual immaturity in designers and analysts if they believe in an ideal mental image of this, that or the other.
The flexibility of mind that comes with realising that any situation in the world can have multiple, equally valid, mental representations; that each such representation can be realised in code multiple ways; and that situations, images of them, and realisations of images can, do, and should change over time is crucial to success in systems building. Both in terms of building successfully, and of building systems that succeed.
The ideal can be personal. A diagram optimized for head A may look different from one optimized for head B, for example.
UnderstandingComputersAndCognition explores (amongst other things) the dangers of getting too wrapped up in building mental models of any sort, but especially "ideal" ones.
The book Controlling People by Patricia Evans ISBN 158062569X describes this phenomenon with the metaphor "You're not Teddy." Briefly: Humans tend to build up mental models of things; that's how we make sense of the world. But if we build up a mental model that exists only in our minds and is not grounded in reality, then reality acts in a way that is outside our mental model, that's very disorienting. Healthy people adjust their mental model; unhealthy people (for whom the model is deeply ingrained) try to push reality back into the form of their mental model.
The term "Teddy" comes from the specific example of a person with an imaginary friend named Teddy, where the person projects that imaginary friend onto his or her relationships. That works until the friend doesn't act like Teddy, at which point the original person mentally cries in dismay, "You're not Teddy!"
This can explain a lot of abusive and otherwise controlling behavior.
This occurs often online. Online forums are full of people crying "You're not Teddy!"