One universal antiviral to rule them all?

I always wonder this and maybe people in the comments here know the answer: If humans had the technology to eliminate all viruses on Earth, what would be the outcome? Do viruses keep other bad things in check? Would there be bad consequences if we eliminated all viruses?

Population control.

Not really. Races don't exist biologically. There are certainly traits within populations but that's a bit like my cousins tend to be fatter than my family. It's not something that can be accurately targeted.

You'd be surprised. There is quite a bit of polymorphism within the human species that is very much distinguishable per population. E.g. haplogroup analysis or microsatellite analysis is remarkably accurate in this regard due to a lack of interaction between far flung populations until quite recently in human history. Now, does this imply all the bullshit eugenicists and other racists tend to preach about with race? Hell no, social factors are responsible for most of that variance, but to suggest there would be no biomarker for "race" in its colloquial definition as proxy for population of origin is inaccurate.

This is also why there is a big focus now to seek out underrepresented populations in genetic analysis, because there may be population specific biomarkers that are relevant in disease that you miss if you limit yourself to the handful of widely sequenced homogeneous populations (e.g. there are Utah and Iceland datasets that are popular to use for this).

What there isn't is a small number of distinct subgroups that are more related to each other than to the other subgroups.

Sure there are. An easy example is Australian aboriginals. They were geographically isolated for tens of thousands of years. Their subgroups are more related to each other than to other subgroups.