If you read GAFCON's "The Way, the Truth, the Life" (484kb PDF) and Bishop Duncan's opening address, "Anglicanism Come of Age: A Post-Colonial and Global Communion for the 21st Century" (100kb PDF), you will encounter what can be regarded as one very significant contradiction: The writers of "The Way, the Truth, the Life" state, "The Anglican Church has always been a confessional institution..." whereas Bp. Duncan says, "Anglicanism is neither papal, nor confessional, it is rather apostolic and conciliar."
GAFCON's detractors may well see this contradiction as an opportunity to allege that those who are busily involved in crafting a new global Anglican future cannot even agree on the nature of Anglicanism's past and present identity. And, of course, there are those, from both the liberal and Anglo-Catholic camps, who have never liked the idea of Anglicans being a confessional people. It was considered a virtual article of faith in the Confirmation class I attended that the Articles of Religion (the 39 Articles) were in no way to be viewed as a confession of faith, such as the Augsburg Confession is for Lutherans or the Westminster Confession is for Presbyterians.
Such a view denies the obvious role that the Articles of Religion have played in both defining and describing the nature of a Reformed Catholicism that was no longer Roman. The fact that assent to the Articles is still required of those being ordained in the Church of England, and that, until 1824, assent was even a requirement for holding civil office in England, makes the Articles the nearest thing to a confession of faith possessed by the Anglican tradition.
But what about the future? Is the future of orthodox Anglicanism to be seen as confessional (as suggested by the authors of "The Way, the Truth, and the Life") or should it be viewed as conciliar, as articulated by Bishop Duncan in his plenary address?
I would argue that this apparent contradiction need not be an actual one. There is a strong case to be made that the two views can be reconciled, and the future identity of orthodox Anglicanism will be stronger and more complete if this happens.
Anglicanism should be seen as confessional in this sense: Can anyone imagine an orthodox Anglican future that is not grounded in the 39 Articles? If a movement is to be recognizably Anglican, it must stand in the theological tradition of historic Anglican norms. Those norms should then be expected to form the boundaries that determine who may participate in the councils of Anglicanism and what subjects may be considered.
To draw an analogy from history: Can anyone imagine that someone who did not subscribe to the doctrinal outcomes of the First and Second Ecumenical Councils (Nicea  and Constantinople ) would have been invited to the Third Ecumenical Council (Ephesus )? Would those who failed to assent to the previously established consubstantiality of the Son with the Father have been permitted to engage in further discussions of the nature of Christ, the Holy Spirit and the Trinity? Neither were later councils free to reopen these decisions or go beyond the boundaries (in the sense of straying from the confessional declarations) set by the earlier councils.
Thus, the two models of being both confessional and conciliar worked together in a complementary fashion as godly leaders, united in the confession of one Faith, led the Church in its Gospel mission.