But I came across one justification that blew away all my objections.
Namely, the House of Representatives was originally designed to grow along with the population.
If it had been allowed to keep growing, then that "built-in advantage" of less-populous states would have dissipated. In other words, that built-in advantage wasn't actually built-in. The system was designed to degrade it over time.
In other words, if it had continued as it was, we'd have somewhere around... I forget, 3500 - 4000 representatives today. And that would change the electoral college calculations, to the point that they would almost exactly mirror the popular vote. It's asymptotic, but as the population grows, the (unrestricted) EC approaches the popular vote. It's worth noting that if the house of reps had been allowed to keep growing, Gore would have beaten Bush via electoral-college counting, hanging chads be damned.
So there's nothing sacred about the less populous states. Their advantage only exists because of the much-later agreement to freeze the growth of the house of reps.
Even more interesting, they note that the Constitutional Convention did consider electing the President by a direct national popular vote, which proposal failed by... wait for it... one vote.