As some discussion above, a too short downtime window may not be practical to validators. We consider that a 12-18-hour for downtime allowance is reasonable as a fast swap in/out of active set for validators may not be benefit to the chain.
Given that the window is big enough, increase of Min Signed Per Window is acceptable too. Signing blocks is our obligation to our delegators, right?
We will vote a yes to this proposal and also agree that this topic needs to be keep discussion and fine tune as the block time is reducing and there is room to improve the chain and validators performance.
Thanks for bringing up the discussion and proposal!