Trusted/senior users (narrow focus)
"I guess for now my main point is that we should not idetify admins with this pool of experienced editors" - yes, 100%.
Many admins of course are competent or very competent content editors. Many admins have GAs and FAs. It's a classic Venn Diagram - 1/ good and capable balanced content writers who aren't or won't be admins, 2/ admins who won't meet our criteria for trusted/senior content writers, and 3/ some who are considered both. But the primary criterion here is zero to do with adminship. It's all about "can they be put down on any topic, any content related issue, and they'll understand core policies and try to apply them with care and thoughtfulness, and support and foster good editing and good collaboration." It's deliberately offsetting adminship, as a completely separate route for content writers, fostering a quality oriented community.