It seems that Justice Renato Abad is the upcoming Supreme Court Chief Justice and for legitimate reasons. One, Abad is extremely competent. Two, Abad will only stay for two years which will allow Aquino to appoint his most preferred candidate for the post---Department of Justice secretary Leila de Lima. Why De Lima? De Lima does not have any vested interests to pursue. That explains why Pnoy wants a de Lima there.
Inspite of several pressures coming from one group within the palace for a Carpio appointment, Pnoy is somewhat skeptical. For one, it is widely perceived (or known) that Carpio has many business interests. Justice Carpio founded "The Firm" which flourished during the time of Arroyo.
Pnoy does not want his name entangled with another Carpio-instigated mess. That is what happened with his predecessor.
With Abad, Pnoy is safe.
Truly, Pnoy wants to entirely cleanse the judiciary so that Justice will always be on the side of Right.