Are we talking here about HBD controlled and owned by HIVE as an organisation, or by individual investors ?

I don't like the idea of locking HBD on individual investors, because at that point it's not your HBD any more.

Something I would support is having two savings options.

The first would be the "standard" one we have now, with 20% APY and a 3-day unlock.

The second (new) option would be to stake HBD in a similar way to how we stake HP now, with a slightly higher interest rate, but unstaking would be a slow drip-feed over (say) 13 weeks. This would allow investors to take some earnings out, but would be slow enough to not have a significant impact on price stability.