There actually was talk of direct election of the Executive in the Philadelphia Convention. Ultimately, however, small-state delegates (including Connecticut’s) won the current apportionment of the Electoral College. That’s why my vote for president weighs much more than the vote of someone from California: while Connecticut gets 7 electors (for its 5 reps + 2 senators), California only gets 55 electors (53 + 2), so that what for Connecticut is a 40% bonus for its senators is for California less than a 4% bonus for its senators.
How to justify it? Try this: http://www.lewrockwell.com/gutzman/gutzman9.html