Just to clarify: the proposed mitigation for the privacy concern isn’t necessarily making the unbonding time long, but that it should be “inconvenient or impossible to unstake on demand” and the staking/unstaking events should be sufficiently quantized in amount and time. Both of these conditions could be satisfied with a much shorter unbonding period. I don’t immediately see a meaningful difference in privacy between a 7-day unbonding period and a 30-day unbonding period. Rather than debating the minimum unbonding period necessary to address the privacy concern, this initial proposal chooses a conservative number (30 days) and leaves this for further iteration and feedback.
My intuition is that 30-day lockups are way too long. Given the intense focus on shipping and iterating quickly there is a risk of path dependency here: there will be a temptation for things like long unbonding times to accumulate rationales in order to speedrun other parts of the design like social slashing, or for other desires like rewarding ZEC longs. This may lead to the decision becoming sticky. It may then be perilous for Shielded Labs to proceed with design/development of Crosslink under the assumption that long lockups will be tolerated by the community later on.
Of course, Shielded Labs can work on whatever they’d like. As Zooko said, it’s up to the community to give a yes or no vote to the final proposal. But the community’s veto power also has more teeth if signals are gathered early on. The purpose of this announcement is to solicit that feedback, but then anything that emerges as contentious may deserve early feedback directly from coinholders.
I do appreciate the careful thought that has gone into the proposal so far, particularly the privacy consequences!