Should we start using Helios for public-office elections? Maybe US President 2016?
No, you should not. Online elections are appropriate when one does not expect a large attempt at defrauding or coercing voters. For some elections, notably US Federal and State elections, the stakes are too high, and we recommend against capturing votes over the Internet. This has nothing to do with Helios itself: we just don’t trust that people’s home computers are secure enough to withstand significant attacks.
It's conceivable that you can build a formally verified hardware device that handles the actual voting, and you probably also make sure that the software running on this device is all signed and authenticated with your trust rooted in hardware. And you can then secure your connection to the voting servers using this hardware device.
It would be very expensive, and you still can't be sure you don't have bugs, but it would address a lot of the concerns you're raising.
Should we start using Helios for public-office elections? Maybe US President 2016?
No, you should not. Online elections are appropriate when one does not expect a large attempt at defrauding or coercing voters. For some elections, notably US Federal and State elections, the stakes are too high, and we recommend against capturing votes over the Internet. This has nothing to do with Helios itself: we just don’t trust that people’s home computers are secure enough to withstand significant attacks.