The existence of the Senate is a moral wrong. Otherwise, I'm not sure there are any moral wrongs in the Constitution as it is right now.
The Electoral College system is morally wrong too.
How so?
Basically, it's a violation of the "one man, one vote" principle.
How so?
Because a person from Wyoming has over fifty times as much voting power in the Senate as a person from California. (Or a person from Vermont has over thirty times as much voting power in the Senate as a person from Texas because you'll be partisan about it otherwise.)
In other words, effectively, every resident of Wyoming can vote over fifty times, but every resident of California can only vote once.