i do not think these concerns are legitimate any longer. if internet security was impossible then my bank account (along with others) would have been hacked long ago. everybody banks online. this is just conservative backlash. the real problem with elections is that a lot of people do not bother to vote, which put the legitimacy of the elections into question. online elections can help solve that.
I would rather have people staying home than casting random votes based on their emotions, or who they happened to see on billboard on their way to voting point.
Voting should be a conscious effort, so making it too easy to vote is counterproductive.