If we ever get to the point where dissenting opinions of regular stakeholders are not penalized, I would be in favor of an idea similar to yours where witness votes expire after an allotted amount of time. Unfortunately, the very first thing someone would do is make a dApp for that, making the plan not entirely foolproof. Perhaps the blockchain would need to incorporate some kind of image dealio that will test if you are human before a voting session expiration. Thanks for sharing your ideas @badshadow!