That would be a utilitarian legal system, trying to maximize utility/happiness or minimixing pain/harm. I’m not an expert on this field, but there is a big literature of comments and criticisms of utilitarianism of course. Whether that is evidence enough that it is a bad idea is harder to say. Clearly it would not be feasible to implement something like this in western democratic countries today, both because on the emphasis of human rights but also (and this is probably more strong) many people have moral intuitions that it is wrong to act like this.
That of course leads into the whole validity of moral intuition issue, which some of my Oxford colleauages are far better placed to explain (mostly because they are real ethicists unlike me). But basically consequentialists like Peter Singer suspect that moral intuitions are irrational, while moderates like Steve Clarke argue that while they can contain relevant information (but we better rationally untangle what it is) and many conservatives regard them as a primary source of moral sentiment we really shouldn’t mess with. I guess this is where we get back to overcoming bias again: many moral intuitions look a lot like biases, but whether they are bad biases we ought to get rid of or not is tricky to tell.
My personal view is that this kind of drafting indeed is wrong, and one can argue it both from a Kantian perspective (not using other people as tools), a rights perspective (the right to life and liberty trumps the social good; the situation is not comparable with the possibly valid restrictions during epidemics since my continued good health does not hurt the rights of anybody else) and a risk perspective (the government might with equal justification extend this drafting to other areas like moving people to undesirable regions or more dangerous experiments, and there might be a serious risk of public choice bureaucracy and corruption). The ease I had to bring up a long list counterarguments of course shows my individualist biases. But it is probably easier to get people to join this kind of trials voluntarily simply by telling them it is heroic, for science/society/progress/children—or just pay them well.
I’m personally interested in how we could do the opposite: spontaneous, voluntary and informal epidemology that uses modern information technology to gather data on a variety of things (habits, eating, drugs taken) and then compiles it into databases that enable datamining. A kind of wikiempidemology or flickrepidemology, so to say. Such data would be far messier and harder to interpret than nice clean studies run by proper scientists, but with good enough automatic data acquisition and enough people valuable information ought to be gathered anyway. However, we need to figure out how to handle the many biases that will creep into this kind of experiment. Another job for Overcoming Bias!
This two-side bias appears to fit in nicely with the neuroscience of decisionmaking where anticipatory affect appears to be weighed together to decide wheter an action or option is “good enough” to act on. For example, in http://sds.hss.cmu.edu/media/pdfs/Loewenstein/knutsonetal_NeuralPredictors.pdf there seems to be an integration of positive reward in the nucleus accumbens linked to the value of the product and negative affect related to the price in the insula, while and medial prefrontal cortex apparently tracks the difference between them.
There is definitely room for a more complex decision system based on this kind of anticipatory emotional integration, since there might be more emotions than just good/bad—maybe some aspects of a choice could trigger curiosity (resulting in further information gathering), aggression (perhaps when the potential loss becomes very high and personal) or qualitative tradeoffs between different emotions. And the prefrontal cortex could jump between considering different options and check if any gains enough support to be acted upon, returning to cycle if none seem to get quite the clearcut support it ought to.
This makes a lot of sense from a neuroscience perspective, but as an approximation to rationality it is of course a total kludge.