Like a proposal that never expires and is updated every month or two and has the following options:

1. Up
2. Keep
3. Down

If the up wins, increase the apr to 0.5-1%, If the Keep wins, just let it untouched, and if the Down wins reduce the apr -0.5-1%.

And some mechanism so that you can 'keep' your vote without having to renew it after each reset. But that after a year it expires and you have to vote again manually (in case of lost keys, death, etc).

This way the APR would be predictable within a timeframe of 6-12 months more or less, and it would be ideal to increase it as we 'feel' the peak of the bull market approaches to incentivize the people to sell before the inevitable crash and reduce it as we bottom out to incentivize people to move to HP.