Eric Posner and E Gley Weyl have posted a paper on SSRN, Voting Squared: Quadratic Voting in Democratic Politics. They recommend quadratic voting as a way to solve preference aggregation problems by taking intensity of preference into account.
Quadratic voting has long interested me. Back in 1996 (before campaign finance voucher proposals became fashionable) I proposed campaign finance vouchers in a California Law Review article, Clipping Coupons for Democracy: An Egalitarian/Public Choice Defense of Campaign Finance Vouchers, 84 California Law Review 1 (1996). I proposed that voters each be given $100 in voucher dollars to give to candidates, parties, or interest groups, but the groups would receive only the square root of the value. (Thus, one could give $10 if given to one group or party, but if spread among four the total value would be $20 (four $25 contributions each worth $5.) I offered a detailed defense of this proposal.
In retrospect, enacting vouchers would be complicated enough without having voters figure out square roots. But I still think the idea is sound.