Yet another PR move on Zuckerberg's part, he is still 100% holding onto his power at Facebook. Facebook simply cannot change, because the incentives for running that kind of service don't align with instituting actual good moderation on the site. I doubt anybody is under the illusion that this so-called "oversight board" will have any impact on disinformation spread and arbitrary removals, or do anything serious in terms of policy due to the impact that would have on Zuckerberg's position.
I feel like it is more of a sockpuppet created to keep as much of the blame away from Zuckerberg and his company while attempting to defuse the risk of actually meaningful regulatory protections against disinformation. As long as there is an incentive model where advertisers pay for attention and Facebook delivers it through outrage, nothing will change.