I'll tell you what's wrong with it -- the Dems have something to whine about "She won the Popular Vote! Illegitimate president! Abolish the Electoral College!"
Even if you live in D.C., you should go give one more vote for Donald Trump. Just as a vote for "Pro-life is better than Abortion" if nothing else.
Think of it as a vote for God's order vs. Satan's order. We all must have a strong opinion there.
That is precisely why I intend to vote for Trump. I live in a "safe red" state and Trump will win it, no matter what. However, as you point out, Democrats grieve their hearts to death over the popular vote, simply because, as things have turned out, probably less than a dozen largely rural, conservative states have an outsize effect upon the election, while liberals tend to cluster in cities that influence their state's election in only a few states. There are plenty of conservatives in California, but it doesn't matter, because they are outnumbered. Ditto for New York State. Every vote for Trump is one more vote towards giving him a popular vote majority, and thus de-gutting one of their central tenets. If, hypothetically, the set-up of the electoral college favored them, you wouldn't hear a peep uttered by them against it.
The Constitution, as it was originally written, makes no provision whatsoever for Presidential elections or the popular vote. The original template, so to speak, was for state legislatures to select a slate of electors (the same way they were to select Senators). Those electors would be solons of a sort, wise men who would then seek to select a president. If they failed, and it was foreseen that they might, then the Federal Senate and House of Representatives would step in and select the president and vice president respectively. The Constitution does not provide for parties either. Things have morphed into something entirely different, and liberals and other "progressives" want everything to be done by popular vote. This is even beyond what most liberal European democracies do --- they have complicated systems of proportional representation which then select prime ministers without the voters having any direct say-so either.