Electors are not chosen at random from the phone book, nor do they make their pledges idly. These are party regulars, personally and politically committed to the party whose nominee they have pledged to support. They are not going anywhere.

If there is a risk, it's that a secretary of state will refuse to confirm a winning slate and the state legislature will step in to name electors. That would be a mess. But faithless electors? Nah. Not gonna happen.

As for the sounds-good-fast critique of the EC, the device merely blends the voting power of the House and Senate. If the EC represents "land," then so does the Senate. Low-density and high-density industries need to be balanced. The EC and bicameral legislature make that possible. More about that here.

Slavery, of course, is a red herring waved as a red flag. The EC protects agricultural states from the tyranny of industrial states. As it happens, the agricultural states practiced slavery, but if they hadn't practice slavery, they would STILL have demanded a senate and EC to protect their interests. Slavery was their issue, but if it weren't, something else would have been.