From the third paragraph of the AP news article:
The change means conservative Anglicans from around the world will be able to join the Catholic Church while retaining aspects of their Anglican liturgy and identity...In our language, the Vatican is deliberately reducing the costs of switching from Anglicanism (Episcopalianism in the U.S.) to Roman Catholicism by making it possible for Anglican switchers to retain more of their religious capital.
A simple prediction is that this new Vatican policy should lead to more switching from Anglicanism to Roman Catholicism. I expect this will be the case, however, there are mitigating factors. An important one is the perceived trajectory and timing of changes in Anglican policy. If policy is expected to change in the direction of supporting, say, same-sex marriages, then there would be more switching today than there would be without such expectations. Moreover, some people may seek to remain Anglican until policy changes actually occur, staying in the meantime with the hope that the policies will not change. The bottom line is that the exact number of switchers might not be very large initially, and the total number of switchers over the course of the next years will depend on the timing of the changes, if any, in Anglican policy.