I differ from many (most?) of my left-leaning/liberal/progressive friends in not wanting to chuck out the Electoral College and replace it with something like a national popular vote. One way to think about this is a change from lots of relatively small contests to one big one. In a way it's like the difference between a football game and the baseball world series. In football it doesn't matter how many quarters you win - only the complete tally of points matters. In the World Series the total number of runs scored is irrelevant in that the winner of the series is the first team to win four games.
On the face of it, the EC is profoundly undemocratic. Shockingly, we don't live in a (direct) democracy. We live in a republic. There are, for example, no national referenda in the way that California and other states permit direct popular majority voting. Our elected officials represent us in matters such as how our tax dollars are spent, what treaties are negotiated with foreign powers, and so on. The EC is a particularly poor form of republicanism in that the electors aren't themselves subject to popular vote nor are they answerable to the citizenry for their actions but I think it's a difference of degree, not kind. The problem I see with the EC is not that it's undemocratic, but first let's talk about other alternatives.
National popular votes are usually proposed as alternatives to the EC, but they're also problematic. We've seen people pass all kinds of idiotic things by popular vote, not least of them revoking civil rights of gay people, crippling schools by prohibiting revenue measures, and so on. In addition, a national popular vote for president would be just as subject to manipulation as current popular votes. Remember how the Mormons poured millions into meddling with California's vote on marriage equality?
Right now the Democratic party is unpopular overall. Governor's races are actually state-wide popular vote contests that aren't affected by gerrymandering (but are affected by voter suppression) and the Democrats control a only 18 governorships. I couldn't easily find the incoming numbers but even with the squeaker in North Carolina going to Democrats I suspect that won't change much. If you believe the popular vote tallies showing Ms Clinton with something like 48% of the vote to Mr Trump's 46% then you'd expect Democrats to control 24 governorships. Senate seats are closer, but still show a lean against Democrats.
The problem is that the Democratic party is much more popular in its regions than the Republicans are in theirs. Sum up all the "overvotes" and it makes it look like a Democratic presidential candidate has a larger appeal than they do.
And that, I think, points to the root of the actual problem with the Electoral College - it penalizes people for their choices of where to live. Very few people choose their state of residence based on national election factors. People live where the jobs are, where the schools exist that they want to send their kids to, where their families are, or where they've grown up and know people/have a support network.
In effect, the EC is a penalty enacted against people who act in their own rational (economic, social, personal) self-interest. I have not seen anyone make this specific argument before, and I'm not sure that it convinces me the solution is to ditch the EC in favor of some kind of NPV. Perhaps a better solution would be to mandate proportional allocation of electors in all states rather than winner-take-all. That would still involve a penalty of some kind, but it would be a lesser penalty.
And maybe that's an OK penalty because we want to elect a president who will represent (or at least appeal to) people who make a variety of rational self-choices, not just the most popular such choices.