Our voting system really does need a complete overhaul, especially as you point out in the area of state-by-state differences. 

There are many options that come to mind:

1. Make all states consistent - and all would have early voting, including by mail. All would have automatic registration at certain events like driver ID or for selective service. 
2. Paper trail, every where. Possibly backed up by a cryptographic scheme (blockchain?) in which voters can be check that their vote was properly counted. 
3. Stop weighting the people in flyover states higher than those in more important states. If we are going to weight anything, it should be the reverse. Why should backward states be permitted to hold back places like California? If anything, California should be able to force others' progress. Every state has two senators regardless of size so that should be enough.
4. Use ranked-choice voting.
5. Get rid of gerrymandering. 

Naturally, the right focuses on voter suppression instead.