AR to bring up extra data would be great, but it might be tricky get clear, unbiased, sources of information.
How they plan to spend the budget, as a pie-chart, for example, would be nice.

The only danger I see here is in the far future, when we all wear AR specs that are absolutely perfect.
Then we could be tricked into ticking the wrong box, by a various that changes the text we see on voteing day.
(“unaugmented eyes only” might have to be a rule in the polling bothes :P)

That said, this could be useful/used if HMD’s become ubiquitous. Imagine the candidates head, along with info on their party and major political stances, popping up on top of the ballot. May not be necessary for major candidates, but it could lead to more informed choices about all the minor offices no-one ever knows anything about.