I would have given Arinze a 50-50 chance prior to 9/11. But I think the College of Cardinals etc have been deeply affected by 9/11 and all that it has entailed; and so election of an African pope, attractive as it may seem at some levels, is not (for me) the top priority among the electors. I predict a young-ish European, no older than 72, who will represent historic "Christendom" against the other major forces in the world (Islamo-fascism; Western Consumerism; Socialism; and Tribalism). My prediction: Paul Poupard. IMHO
The needs of the Church are not the needs of Europe, and John Paul II has seen that the College of Cardinals is very diverse in terms of geography.
I think that Africa is the focus of Christianity these next few decades, and having an African in the Holy See will be a profound statement. The focus of the poverty, disease, and chaos that runs rampant through Africa will be able to be brought into sharp focus by a Nigerian Pope the same way that the despair and oppression of Communism was revealed by a Polish Pope.
Islam and Christianity will be engaged in a mighty struggle if Arinze ascends to the Seat of Peter, and it will be in West Africa that the conflict will be the sharpest, not Jerusalem.