Some variation of this sounds much better to me than the proposal to simply change the powerdown time from 13 weeks to 4 weeks.

I don't believe a simple change to 4 weeks would have much impact, because even four weeks would be too long for anyone who wants to speculate on a volatile market situation (in crypto these opportunities often only last for days or even just a couple of hours).

An instant powerdown would be the only option that I think would satisfy the need for those who want to free up funds to speculate. I agree there should be a fee associated with instant powerdowns. And I think your idea to pay that fee to those who stay powered up, as an incentive for them to continue to hold, also makes a lot o sense.