Combining the suggestions from 1 and 3 is where things fall apart for me. If the statute does not specify what objective standards must be met in order for someone to be eligible to vote, then the ruling party gets to decide on their own.
Maybe the next updates to the standardized test just “accidentally” favor the ruling party.
Another older blog post saying the same: https://sandimetz.com/blog/2016/1/20/the-wrong-abstraction