There will be much conversation about this missive in the hours and days to come, but for starters I don't think we can do better than Mark Harris' concise summary:
The message to the Primates continues the Archbishop's slow dance around the issues troubling the Anglican Communion. It is a difficult document in that it leaves us with little to go on except that: (i) he thinks the Episcopal Church (TEC) has gone about as far as it can go at the moment, (ii) he is puzzled why bishops in TEC can't just make decisions concerning ordinations and blessings on their own, (iii) that Bishop Robinson (who the ABC calls Gene Robinson, finding it difficult to acknowledge that Gene is indeed a bishop) is still not invited as a diocesan to Lambeth, and (iv) there may be bishops uninvited to Lambeth still, as well as bishops uninvited to engage in the life of the Communion, on the basis of their enthusiasm for the Windsor and Covenant process. The letter is something of a mess and a disappointment.
What Mark said. AND note that the Archbishop's suggestions for moving forward NOWHERE includes the voices of the gay and lesbian faithful the Anglican Communion has been committing to "listen to" for the last 30 years.
More to come.