You are correct in the first part. The south wanted slaves counted fully. The 3/5 compromise reduced their influence in the EC.The south wanted it both ways…hold them as property, but count them like citizens. Maybe PA should have demanded that horses were citizens. In any case, the 3/5 compromise is now moot. The same should be said for the EC. Both are anachronisms whose time has passed.
You are incorrect in the second part. What is left of our republic is dependent on protecting what is left of federalism, and defending against the dangers of democracy and strong central government. The electoral college is critical in that.
google.com/amp/s/www.washingtonpost.com/amphtml/posteverything/wp/2016/11/15/in-defense-of-the-electoral-college/?client=safari