Thank you for talking about DALYS and QALS; It is really important to highlight that health economics is the discipline which deals more with disease burden measured by financial cost, mortality, morbidity and other indicators. Data from Measures of population health such as life expectancy, disability life expectancy, etc.... are key components for decision making related to appropriate and effective policy in health care system.
For principles; what do you mean by Discounting in Health care system; If it is to adjust future cost and outcome of health intervention, it is a good approach/principle but not always applicable Let's take example of new or advanced technology used in health care system that should be imported from outside the country or an intervention that requires to be done outside the country; the Discounting principle would be difficult to be applied.
Adding to this approach i would highlight the community's involvement in the health care system such as strengthening and increasing the community health insurance coverage and the pocket out payment for service delivery.