The electors only exist because it made it possible to hold a vote across a large nation in a time when horses were the fastest mode of communication. And each elector was supposed to carry the results of the same number of voters.
But the country has grown, with some states growing in population much faster than others. Yet the number of electors remains unchanged. Not to mention electors are now completely unnecessary as we have fast and reliable communication methods.
I would disagree that senators and congressmen are just vote messengers. They run on active platforms, respond to changes in their constituencies (hopefully), deal with new issues as they arise.
Electors literally just ferry the states vote to Washington, that's it and job done. Representatives continually represent the will of their constituents through multiple years, or at least that's what they are supposed to do.