Changing the Church's teaching on divorce would be anything but merciful
There is a Synod on the family currently taking place in Rome. It has been convened by Pope Francis and it is really a continuation of a Synod (or meeting) on the same topic that took place in Rome this time last year.
The purpose of the Synod is to discuss the challenges facing the family in all the parts of the world the Church finds itself in and to work out the best way to help families meet those challenges.
Therefore, the Synod has been discussing everything from migration, to poverty, to polygamy, to same-sex marriage, to divorce.