I'm personally in favor of something like an annual vote renewal requirement (with a few month vote decay after that year period if not re-voted, as suggested by Michael Vandeberg at last SteemFest). But it's certainly not the only option out there.

I hadn't really thought about applying it to proposals, but it might make sense there too, since some people do make proposals with super long terms (generally something I'm not in favor of, I think proposals should generally be limited to a year anyways,and then just submit a new one if necessary to continue work).