While this has been in the works for some time, apparently the suddenness of the pronouncement took our Episcopalian brethren by surprise. An added wrinkle was including Episcopalian seminarians in the mix, although their priests would require ordination into the Roman rite. One Brooklyn priest here heard as many as 300,000 Episcopalians are prepared to jump ship. How many of ours have gone over to them was not discussed, although a few years ago NCR published a figure that suggested for every one of them that comes to us, ten Catholics go over to them.
The unspoken elephant in the room (See? I can keep my mouth shut) is why these people are leaving the Anglican communion: dissatisfaction with their church's position on women priests, openly gay priests, and blessing same-sex unions.
There would no doubt also be an influx of married clergy from the Episcopalians which, IMO, would put incredible internal pressure on the Vatican to rethink and relax mandatory disciple for our guys. If not, we face the anomaly of our guys in formation struggling with celibacy and being advised to leave, join the Anglicans, marry, get ordained, then come back. But I guess stranger things have happened in Holy Mother Church.