There are any number of ways to apportion power in an election. For example: Each state gets one electoral vote.
Would the electoral college defenders support that apportionment of power? If not, why not?
Or, what if a state elected their governor based on a county based electoral college? Would that be a good idea because it preserved the power of small counties?
Obviously, those ideas are ridiculous for the same reason that the electoral college is ridiculous.
The President is today truly the leader of the entire country. There is no principled reason to give Delaware and Wyoming greater power in deciding their President. The only reason is a desire to protect your narrow political interest or a belief in tradition for tradition's sake.
State lines often have some historical and cultural significance. County lines are much more artificial, usually aligning with parallels of latitude or meridians of longitude.
Most of the Western states were arbitrary creations designed to give the party that was in power an advantage in the electoral vote.
The electoral college system is so ridiculous that I honestly think anyone who supports it is either an idiot or a hypocrite.
The line between Colorado and the pair of Nebraska and Kansas was put there for a pretty good reason involving cultural differences. On one side you had the nice farmers that had gotten there thanks to the Homestead Act and were of a pretty moralistic Protestant background. In what became Colorado, on the other hand, you had society's underbelly in a sense: wild miners that founded the towns you see in cowboy movies, blah blah blah, and that line officially separated the two.