Within the Evolution: Proposal Reviews folder, perhaps each review thread could be placed into its own subfolder (i.e., a folder labelled with the review title and number). If a debate or counter-proposal warrants special attention, the review manager could create a new thread, in the same folder, with a title that solicits input on the specific debate/counter-proposal.
That new, targeted thread will float to the top of the Evolution pile. By virtue of its title, it should grab attention. By virtue of its focus, it should generate the desired feedback.