Problem

The ideal curator is someone who loves the platform and understands what will make it a success long range. A person that thinks rationally about curation with a long-range perspective. We don't want opportunistic people who are short sighted whim worshipers in a position of power. The incentives with respect to powering up and down should, therefore, be aligned to promote this outcome.

As it is now a short-sighted person might power up in a moment of elation and regret it the next day. With a delay on powering down, we are preventing the emotional short sighted whim worshipper from exiting a position of power quickly.
This keeps a lot of toxic people locked in a position of power that might not have the long range interest of the system in mind.

The solution is to filter for patience

If it was possible to power down almost instantly but the power up period was long-ish, it will only be people who truly are committed to the long-range success of platform that will take the time to get into a position of power. Everyone else would quickly power down and become liquid.

An instant power-down period would also be able to supply the market with liquid STEEM in a situation of high demand and it would facilitate a wider distribution of the token instead of having it locked up in a few bigger accounts.

I propose a linear gradual power-up period of 52 weeks and a power-down period of a few days.