Why do we level the playing field between rural and urban, but not along any other axes? There are plenty of demographics that are disenfranchised by their relative size, and they would gain important safeguards against oppression by having a louder voice. But we don't, for example, count black people's votes eight times to put them on a level playing field with whites. The electoral college doesn't make the whole system more fair, it just tips the scale in one particular direction.
Also, the idea that if you don't like a state you can just move is meaningless in this case -- we're talking about the results of a federal election. You can't move anywhere to escape those, so that suggestion doesn't weigh on electoral college considerations.