Another angle is that when an election is close (battleground states), then we can say both candidates (or their electors) more or less have the same credibility to the people of that state. If the contest is indeed a coin flip on election day, then can we really say that one party was vastly superior to another? Either by communication of policy or vision or by better electioneering skills?

I recommend reading Jerry Springs with his essay on Equal Voice Voting. He has some interesting angles on reforming the electoral college.