Right now, we have a situation where the "house" picks claims that it thinks are good for the site. The economic incentive there is to create claims that will attract a high degree of betting and bring traffic to the site.
I would suggest there are issues people may want to get market feedback on for which they would make payment to get that feedback. That might be handled by
a) a claim creation fee for ideas that have not been implemented
b) a subsidy allocated to the first x dollars of transactios in that claim
c) a prize allocated among those that bet on the right side of that
B&C mean that on average traders might have net positive cash flow from betting on that kind of claim(if the volume was low)
This is a different revenue source for the site and could generate extra revenue for traders.
For example: political campaigns might then use the site to do market research on elections or metrics that would otherwise not be attractive to traders.