If what you want is a "None of the above" option, then advocate for a none of the above option! http://nota.org/
Don't vote for an arbitrary non-incumbent who may well be a worse politician.
Don't vote for an arbitrary non-incumbent who may well be a worse politician.
Basically, you still have only one vote, but you can use that to cast a negative vote against a candidate, rather than a positive one for a candidate.
It's the simplest way to break the monopoly of two parties because a negative vote against a major candidate has the exact same practical effect as a positive vote, but without perpetuating the two-party system. Best of all, those who are afraid of change can vote with a positive vote in exactly the same way they have in the past, with the same effect.
Here's the big problem with that idea: someone still has to win. Therefore you should vote for the candidate who you think deserves to win. If you don't think any of the candidates deserve to win, then that's a problem... but it's not a problem that "negative voting" solves.