I think voting should be required by law to be in person with very, very few exceptions, and those being extraordinarily controlled and regulated to protect against fraud.

There is an interesting idea here though: if even one of your parents was a US citizen, the United States considers you a citizen even if you were born abroad, never entered the country, and don't even speak English. They expect you to file US income taxes and pay them unless you go through the renunciation process. Thus, purely by accident of birth, the US asserts that it has complete control over you as it would any "real" US citizen.

Given the US government's stance, it's only logical that they would be required to afford you all the rights of a citizen as well, including the right to vote. I'm genuinely curious how they would administer this, since voting is all done at the local level, and you don't have a state, county, or city to claim residence in if you've never even entered the country.