While you are at it, you could perhaps have a single national set of rules for the national election.
Apparently not. Many Americans apparently think that the Constitution has the same status as stone tablets handed down personally by God. They are blissfully unaware of the different contexts involved - that a solution designed two hundred years ago might have been a good idea two hundred years ago, but is inappropriate now.
(The electoral college system was invented because there was no way for the general populace to know much about the candidates - so you elected responsible people who would go to Washington, meet the candidates, and pick one for you. Mass media was unknown at the time.)