A pope emeritus is a creature unknown. Others have stepped down before death but, pace the Church's rules, were forced, and then imprisoned. Then they died. Benedict is going into a kind of perpetual retreat, a life of prayer, thought and - somewhat ominously or promisingly (depending on stance) - writing.
Cracow's cardinal has recalled John Paul II's dictum: you don't get down from the cross. Ratzinger was at Wojtyla's side until the end, forming, implementing, interpreting, assisting. Is this the role in which he excels and to which he aspires again? Many have sought a way to survive their own death, control their own succession and temper their successor. The spiritual (or intellectual, in academic and ideological terms) force of a revered but now reclusive leader is evidenced through history.
Ratzinger has used the powers of the papacy before its assumption. Might he exercise them after he has laid it down? Throwing doves out of windows and waving to every badante in Italy on a visit to St Peter's isn't really his metier. And anyone who has ever been in retreat will know that even a few days of contemplation on themes of power and action in life make for a certainty of view and how to achieve it.