The Essay takes on Godwin’s argument for the perfectibility of man/woman and his/her society, with Malthus bent on showing the folly of Godwin’s optimistic views.
(It is also important to remember that this was an era of the belief that a larger population would produce a wealthier state.) Malthus, with geometrical population growth and arithmetic food increase, argues that the result of a surplus starving population would be reached almost immediately, not in the distant future.
If the world is to be improved, it does no good to play around with utopian dreams where the streets are paved with gold and everyone eats candy without gaining weight or getting cavities.
The solution will require a hard-headed, realistic analysis of the problem, our identifying what we can reasonably expect to work based on what has worked in the past, and our working with what is currently possible given the political situation.
And when we look back at how much has already been done, we can thank Malthus for giving us a head start. The topic broadens into the public policy consequences of his theory and the metaphysical purposes of misery.
Moreover, the writing is excellent; who expects Malthus to have a sense of humor?
People have known that since the dawn of Humans tend to increase faster than they can create food, so at a certain point they will be unable to support themselves.
That general idea is so obvious that it seems hard to believe someone would have to come up with it, and Malthus is just the guy who laid it out most clearly. But he's also been consistently misinterpreted and vilified since day one by people who, for example, think he's advocating policies to kill off poor people.
I also didn’t expect the feminism, and the extension of the analysis from the of the misery produced by the imbalance in population and agriculture.
As a clergyman, Malthus understandably felt it incumbent on him to justify to man the ways of a God who would create such a law of nature.