This is what I would change:

Tie the payment of interest for holding HP to voting on governance. In order to receive interest on your HP you need to vote for block producers and proposals. This would incentivize stakeholders to increase the security of the network.

Use the savings account feature as a second staking mechanism where you can earn interest and take out loans on HBD (for those that are not interested in governance and/or participating in curation. Here the staking period could be must shorter (this is similar to what @edicted has proposed).

With these two options there is no need to change the powerdown period. A four week timeframe to unstake HP is the limit of what I consider safe for the network.

Those who are proposing insanely short powerdown periods seem to forget how easy it was for exchanges to colude during the Justin Sun fiasco.