Archbishop Rowan Williams' role as incumbent of the See of Canterbury gives him a unique opportunity to lead the Communion, a unique opportunity which I do not think is yet undermined by provinces here and there which have sought to remove 'communion with the See of Canterbury' as constitutive of their being Anglican. How might Rowan lead the Communion with a vision for a future which is not 'chaotic and uncertain'?
I suggest that one text needs to guide his every statement and sermon:
"to unite all things in [Christ]" (Ephesians 1:10)
The great plan of God, as articulated in the fullness of Pauline theology within Holy Scripture is that all things are united in Christ. A larger framing of the phrase above is Ephesians 1:9-10:
"making known to us the mystery of his will, according to his purpose which he set forth in Christ as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth."
The future of the Anglican Communion is to be joined with other things in the universe in the great unity of everything. That means that everything in our life together which presents as an occasion for division and disunity is an opportunity, should be an opportunity, as faithful readers of Scripture, for deepening our life together. For and against the ordination of women as priests and bishops? This could lead to division (and in places has), but challenges us to find the ways in which we might remain united together in Christ. Responding to differing cultural movements in respect of human sexuality in general, and homosexuality in particular? A process of division has already begun, but is it irreversible? What might it mean, even now, for (say) ACNA and TEC, or TEC and Uganda to sit around a table (a loaf of bread and a cup of wine placed serendipitously in the centre of it) and talk and listen and talk and listen until unity in Christ is regained, because as Anglicans bound to listen to Scripture we are "eager to maintain the unity of the Spirit in the bond of peace" (Eph 4:3), knowing "there is one body" (4:4) united under just the "one Lord, one faith, one baptism, one God and Father of all" (4:5-6).
Archbishop Williams role, I suggest, is not to articulate anxiety about our future, but to cast and recast the great vision of Scripture for the unity of all things. In respect of that vision we have erred and strayed and gone our own ways. It's time to come back to the one way of Jesus Christ. Our elder shepherd Rowan, on behalf of the Great Shepherd, needs to call us back together. We need to heed that voice, not because of veneration for the heritage Canterbury represents, but because it is the voice of the living Word of God, our Lord Jesus Christ.