I had a great conversation with a client (actually potential) about extending IdeaScale to provide for a costing model for ideas. As is typical with most businesses - feedback and enhancements are not FREE - everything has a cost associated with it. Currently with IdeaScale we are not focusing on capturing either the cost (or value) of any particular idea.
On internal sites, this can be referenced as "Cost Savings" or "Revenue Generation" - Users (both who are posting ideas) as well as voting on them should be able to quantify the cost savings a particular idea will produce.
In some cases, only the idea author may be able to define the cost/value, and in other cases both idea authors as well as voters can define the cost/value for an idea.
One solution to this issue, is to come up with a Numeric (Enter $ Value) Custom Field on IdeaScale and use this as a model for reporting median values etc.