Background: I run a voting precinct in California and have for many years.
Paper ballots are really the best for these reasons:
1) Fits human time frame. a large number of voters make up their mind incrementally. They take the mail ballot and mark the offices/measures that they know for certain on. Come election day they show up at the precinct with almost everything filled out. They then sit down and decide for everything else.
2) Does not require good eyesight. Older voters, younger voters, what ever - a simple magnifier can easily be used. We have them at the polling place.
3) Voter can vote on issues nonsequentially. Voting machines present the issues in the order they are on the ballot - not the order that the voter wants.
4) Speed of voting: if a voter knows how they are going to vote they can fly through a ballot in a couple of minutes. Voting on a voting machine takes a minimum of 6. Add in all the back and forth on the screens and it is frustrating for voters.
5) Ability to handle crushload of voters: If I have a lot of voters ready to vote: I put them anywhere in the room I have a seat, flat surface and a pen. With electronic voting machines I am limited to number of machines.
6) requires no training: everyone knows how to use a pen. Computer program... not so much. And I am not talking about tech sophistication. Anytime anyone uses a new program they have to slow down and make sure they understand what is being asked and what are the choices.
7) clarity of errors and error recovery: if a voter knows if they marked a ballot ( with a pen - not the chad Florida ballots) incorrectly. Error correction is easy.
8) No electricity is needed. Paper ballots always boot up correctly.
-----------
Only reason for electronic voting is for sight impaired voters. And of the sight impaired voters, 100% seem to have solved the problem with mail in ballots OR bringing someone with them to the polling place. (In the 6 years i have run a precinct with upwards of ~2000 voters personally processed by me : about 6 have actually voted electronically)
--------------
If you want to solve the real problem, based on my experience:
1) same day registration/automatic registration
2) easy voting at locations near transit.
3) easy access to mail-in ballots.
4) no electronic voting - much faster to process voters with paper.
5) allow people to vote out of precinct. (don't require people to get home - make it easier for them to vote near where they work)