Appropriate for his audience; and, yes, appropriate for all of us. 
We need to experience mercy, as well as to bestow it.
Perhaps Francis bestows mercy upon the clergy? The changes in CDF could indicate this. 
And he has shown concern for migrants.
He also needs to bestow actual mercy upon the laity (especially survivors of abuse, women and LGBTs) - not just words. 
It seems his hands are tied. Perhaps, like Jesus, he needs the faithfulness of the disciples (clergy and laity) to BE merciful? (We are all rather good at expecting goodness and mercy from others!)