There are still too many unknowns, and you'll still make mistakes in your math.
When the government restricts Mary from infecting Joe based on statistical premises, the government is also inadvertantly (at best) restricting Sally from exercising her liberty. You can make a GUESS about which action will minimize aggression, but without hard limits on the means you're willing to use in the arrogance of your correct judgment, there is no limit to how wrong you can be, and how high the cost of aggression will grow. No Menshevik or social democrat ever thought they'd pave the road for Stalin either.
Hence hard, brutally enforced limits on government power. My goal isn't to make a utopia. It's to do everything in my power to prevent the worst case scenario, which we are approaching.
If I had my way? Hah, as if. Off the cuff:
First, the Constitution would impose stricter limits on the kind of powers government may exercise, and the kind of powers they must absolutely under no circumstances ever even attempt to exercise, Bill of Rights style. Unlike our current Constitution, there would be an explicit, 72-point-font provision stating unequivocally that any politician, bureaucrat, executive, or judge who proposes, votes for, executes, or upholds any law which would in any way abridge those rights, ever, under any circumstances, is guilty of treason, which is punishable by death. There would of course be a trial with the presumption of innocence, but upon proof of guilt, the crime is unequivocally treason, and the punishment is unequivocally death. (This would be the ONLY case of death penalty permitted by the Constitution. Public servants beware.) Furthermore, anyone who attempts to institute, execute, uphold, etc. a law or policy outside the scope of enumerated powers is guilty of sedition, which is punishable by N years of imprisonment and a lifelong ban from any form of public office or public employment. No such provisions may be amended, except to make the mandatory penalties harsher. There are a lot of unspoken details here about checks and balances and the power of the people to easily repeal laws with a sizable minority, etc. Actually writing a bullet-proof Constitution is outside the scope of this post, and actually getting there from here is another matter. If achieved though, it would be a good baseline for a government that stays limited indefinitely, instead of starting to grow without limit from day 1. As a side note, such rules would apply to every level of government, but any powers that could possibly be exercised by more local forms of government would not belong to e.g. the federal government, should such a government even exist (maybe a confederacy is superior, etc.; that's not the point).
There are indeed cases where subjective judgment calls must be made, but the goal should be to minimize these to the greatest extent possible. For instance, within the scope of powers the government may exercise for the ostensible purpose of protecting life, liberty, and property, yes, I would institute upper bounds on the cost/benefit analysis permitted by politicians. Perhaps the Constitution would provide for them to be overridden in extreme cases by an extreme supermajority vote (e.g. 95%) for a duration of no more than one year. The exact numbers, ratios, etc. are arbitrary of course, but that's no excuse to make literally everything arbitrary.
Regardless of the specifics of how I'd defang government if I could: Anyone who uses the argument that subjectivity is unavoidable in SOME cases, as the thin end of the wedge to justify unlimited subjectivity, is no friend of liberty.
We are rapidly approaching the point where a totalitarian government will have the technological control grid in place to make their tyranny eternal...a boot stamping on a human face, forever. That must NOT be allowed to happen, and I will not entertain any bullshit philosophizing that holds the door open for it, least of all from supposed libertarians who are so busy with their own pseudo-intellectual self-fellating that they've forgotten their roots entirely.