The reason there's no easy way to do that is because you have to provide the answer to the meaning of such a visual break. Paragraph breaks are provided, and they have a meaning (change of topic). What does a "line break" mean, as an abstraction, in your mind? When would it come up that I (or other pod authors) would want that meaning?

Well, even TeX provides \\ for simple line breaks: it's a feature one should use parsimoniously (I mean in simple text, special uses are a whole another matter,) but occasionally it can be useful to stress a period ending that must be stronger than a "regular" one and not just as strong as a paragraph break.