Political Philosophy and Harmony

The primary aim of a Political Philosophy is to define the best Polity, which, even if not actual, serves to evaluate systems that are.  Accordingly, what Plato presents in the Republic is an analysis of what many agree constitutes the best Polity--a condition of universal Harmony.  On his analysis, the fundamental feature of that condition is a one-to-one correspondence between what is liked and what is needed, mediated by his observation that, anticipating Aristotle, personal Happiness consists in the exercise of one's natural abilities.  So, universal Harmony obtains when the Division of Labor that is needed is commensurate with the available talents.  That Plato presents that model patently in the text refutes the interpretation of some that the Republic is not to be taken at face value, since, rather, his true doctrine is esoteric, and just happens to coincide with their self-serving political agenda.  Advocates of that interpretation seem to not understand what the primary aim of Political Philosophy is, instead attributing to Plato a smaller-minded ulterior ambition.