What I find troubling about the whole "Cantuar sic et non?" debate is that the focus has been improperly placed on the man who currently resides in the office, with the result that disatisfaction and frustration with +++Rowan Williams (much of it justified) unfortunately morphs into questioning the wisdom of recognizing Canterbury as primas inter pares in the Communion at all.
From my perspective, any debate on whether or not the Communion should remain "Canterbury-centered" is really a secondary matter. So for instance, if, in its common life, the Anglican Communion were one day to decide upon instituting a "rotating primacy" or an "elected head" for itself, then so be it. I'd have no theological objection to this at all. (However, I suspect that if this were to happen Canterbury would still be afforded a symbolic figurehead role, such as that enjoyed by the Ecumenical Patriarch in the Eastern Church, but I digress.)
Maintaining our "Canterbury-centeredness" is not about maintaining ancient prerogatives of an historic see, per se, but about keeping the Communion -- in the present -- from fracturing. Right now, for better or for worse, the Communion has four Instruments of Unity, one of which is the Archbishop of Canterbury. This will not change in the near future short of a schism in the Communion (and then only for those folks that actually go into schism).
Thus any "common-life solution" to the present crisis in the Communion must work within the structures of the Communion itself and with the Instruments of Unity that we presently have. Those who choose to work outside these structures, or through parallel structures that effectively veto the decisions and actions of the Instruments, are not working within the common life of the Communion. Period. In fact, I suspect the only reason we are hearing so much anti-Cantuar rhetoric these days is because such rhetoric serves to rationalize or justify actions from outside the common life of our Communion.