Limits for wikipedia community functionaries but the document doesn't talks about limits for functionaries of the WMF structures.
Seems like nobody knows Meta. The knowledge wide platform could be Meta. Invest in product, improve flow, but don't abandon products.
That a longtime admin could leave is good (and worked in ca.wiki) when they assume new goals and improve other projects. Because they become users with an admin point of view. (jokes about maoism). It is a good idea also for diversity. Longtime admins and patrollers make good tutors.
About leadership: How can we assure the renewal of leaders? We need an environment that assures that. CH should work on what happens when long time leaders feel that the project is theirs and are afrraid that if they leave it would sunk.