This is the fifth time a candidate has won the popular vote but lost the election. I am a firm believer in "not because we have always done it this way, that is how it should be done'. The reason why the electoral college was implemented by our founders was to get candidates to visit states that were not really popular. Logical thinking supports the idea that the popular vote makes more sense.
However, this might be a tough one to get done.
Alena06, the main reason are NY and Cal which usually give Dems a lop-sided victory in numbers. R's don't even bother to vote. However, to say it will remain like that should a proportional rep model adopted is not realistic.
The current system sees most of the campaigning being done in 11 states. Had campaigning been done agressively in NY and Cal by Trump, probability is Trump would have closed the gap and likely still come out ahead.
A shift to a national PR system will basically dissolve the Republic as we know it and reconstruct the nation. That means civil war! It will not happen!!