That pressure would be all the greater were it not for the fragmented opposition in many African states, unable to put internecine rivalries aside to form a united front. Cameroon's Biya, for example, stood against over 20 opponents.
Both O'Connor and Attiyeh acknowledged it could take time for viable opposition forces to develop in some countries, but noted that, unlike two decades ago, all-out boycotts of polls handing the incumbent a walkover were now rare.
Relatively smooth elections in countries from Nigeria and Zambia, which last month led to the swearing-in of opposition leader Michael Sata, are offering Africans proof they can throw out leaders deemed not to be delivering.
Attiyeh said the Arab Spring uprisings, while not emulated further south, had created a sense of impatience for change among many Africans which in coming years may lead to a series of clashes between them and the remaining old-time leaders.
"It is not always going to be smooth sailing," he warned.