Absolutely correct. California has a higher population than over 20 of the lowest populated states, combined, and the top 10 populated states have more than half the country's population, last I checked. Colorado isn't in the top 10.

The President doesn't just represent the citizens, but the interests of 50 different states with their own populations. 

The delegates didn't want the power to elect the leader of this union, the President, to rest in the hands of a few colonies with a large portion of the union's citizens in them alone.