Intellectually I think there ain't gonna be a major exodus because there is no convincing reason for it. An illustrative paired argument, for and against is published in the Guardian. Here is the money quote from the against argument:
"I don't remember ever being in favour of the ordination of women, probably because it struck me that the church was accommodating itself to the ways of the world."
Women priests and women bishops is not an 'accommodation' to the world (with all that implies about declension of commitment to Christ, adherence to orthodoxy, and faithfulness to Scripture). It is an increased understanding of human dignity in the light of God's Word and Spirit - an enlarged understanding of whom God has created and redeemed in Christ: all human beings, male and female, blessed and gifted in the Holy Spirit. In particular it is a recognition that Christ's humanity is the key identification with us in the mystery of the incarnation and cruciformed salvation, not Christ's maleness.
Sure, some arguments for the ordination of women with sloganeering cries of 'Justice' and 'Equality' are an accommodation to the world's talk of progress. But not all arguments are an accommodation in this way. Some arguments work from our new appreciation of the full share in human life which women have with men - an appreciation which asks of Scripture what God affirms about our human dignity and receives from Scripture an affirmation that God created us male and female and redeemed us, women and men, to be one in Christ.
But my point here is not to rehearse arguments for the ordination of women, rather to observe that there are insufficient active members of the C of E who think that having women bishops represents an accommodation to the ways of the world. There will be no major exodus because few are convinced that the C of E is being unfaithful to God by having women bishops.
(For clarity's sake, I am not attempting implicitly or otherwise to mount an argument here that those who oppose women bishops are therefore unfaithful to God. Those like the person cited above who sincerely believe that (for instance) an accommodation to the ways of world is involved in the ordination of women are working from a different perspective on the relationship between human dignity under God and the development of human society in a secularised culture. The arguments that flow from this different perspective are not poor arguments, and the key debate is about the starting point for our understanding of our humanity as men and women.)