If we truly believe in the Holy Spirit’s power to effect reconciliation and conversion, none of us has anything to lose from keeping a very low threshold for motion into and out of communion with the Anglican Core. Indeed, if we love another and hold as a goal Jesus’ will for us to be one, we owe it to the Truth not to erect unnecessary barriers between “staying in” and “moving out,” and (again) to eventually returning.
To this extent, I’m inclined to support the Archbishop’s “two-tier” approach to communion — not because I believe people belong in an inner or outer circle, but because such a proposal befits a transitional stage in which the church discerns the shape of its loyalties. If a congregation could move relatively simply from one tier to the other, we could rely on the Spirit to gather faithful souls where they can visibly, effectively bear witness to the sanctity, faithfulness, and (yes) justice to which all are called.
If in the end, it’s hard to tell the difference between the Anglican Communion and the Episcopal Communion (or whatever one might call the tiers), that itself might tell us something significant about our situation.