This is a great way to manage expiring delegation on top of whatever hard limit (12 or 18 months) is decided for this iteration of this experiment. Simply removing delegate who fall below a certain threshold say 70% over the past 3 months and redelegate those tokens to active delegates would allow systematic increase in delegation to high performing delegates.
I also support a planned approach when it comes to implementing this with the aim of having this change executed onchain before the existing version expires in order to ensure that the DAO remains resilient towards failing to meet quorum requirements.