I do not think the effect will be dramatic. Population density will be slightly higher, but other diseases will take the place of Black Death. Most likely, either Leprosy or Tuberculosis will become the main killers. Not as morbid as Black Death, but as efficient.
Also Typhoid, Typhus, Smallpox, Measles, Influenza, Yellow Fever, Malaria, Cholera.
Only if all of these major killers are removed, one can tell about significant impact on history.
In this case, i expect a stronger church because less dirty and tick-ridden would-be-saints will be dying from the disease. More wars to kill off excess population. In these wars, more mercenaries, as mortality gap between nobility and commoners will be reduced. But also more arts and science, and more long-term land improvement projects like fortifications, dams and irrigation. Not sure about effects on serfdom. Secondary effects on peasant`s attitude due less fluctuating population levels will be most likely swamped by effect of general population increase, increasing the role of Third Estate. So Second Estate (nobility) will be less prominent, so may be no period of absolute monarchies will happen.