According to Halderman* it might take us 10 years, if ever, to get machines the public can trust and verify on the scale that is needed for nation-wide elections.
Given the sorry state of current phone and laptop security, the problem of having a massive TCB is not solved, not with building on Ethereum either.
Recently the CEO of Fox-IT reported a delay to our minister in the Netherlands[2] with researching the specs for a usable and secure vote printer and vote counter[3]. It's not as easy as people think, especially the elder seem to have trouble with it.
[1] https://www.usenix.org/conference/evtwote14/workshop-program...
[2] https://zoek.officielebekendmakingen.nl/blg-604665 (Dutch)
[3] Unofficial translated summary of the report on large scale voting; proposes using a vote printer and vote counter with human readable ballots in between: https://www.kiesraad.nl/sites/default/files/every-vote-count... (English)
My main recommendation if anyone asks with intent to deploy is paper and optical readers. Cheap, easy to use, easy to check at booth, and easy to audit later. I prefer computers stay out of voting as much as possible. However, if they're there, Scantegrity line and Civitas seem like top contenders to build on.
Also note in any analysis that secure voting has so many seemingly-contradictory requirements and attack points that any solution will likely pose difficulties. I expect some responsibility and effort from the system's users just like they must put effort into learning to drive. That said, the usability can certainly improve and we should put every effort into that.