I personally feel instead of spending so much time and effort trying to move closer to Lutherans and other protestants, I think our time and effort would be much better spent making inroads amongst separated Eastern Christians - the Eastern Orthodox, the Oriental Orthodox and the Assyrians.
Full communion with the Assyrians and some Oriental Orthodox is oh-so-close. I think full communion with the Assyrians and possibly the Copts is very much possible in this current century.
Restoration of full communion with the Eastern Orthodox is going to be less likely - particularly because the Greeks and Russians run the show. And the Greeks and Russians are well known for having rabid anti-Catholics in their ranks. And not just rabid anti-Catholics - those same people generally do not even want communion. Some of them go so far as to wishing the papacy abolished and the pope dead. The anti-Catholic EO also are usually fanatically anti-Western, maniacally anti-Ecumenism, and ferociously against any sort of change or reform whatsoever.
But the Copts, and the whole OO communion, is headed by His Holiness Pope Tawadros II, and he is a close friend of Pope Francis. Likewise, His Holiness Mar Gewargis III is a great friend of Pope Francis. I would be absolutely ecstatic if either the Assyrians or any of the Orientals restored full communion with the Holy See of Rome.
Lord, may we all be One even as you and the Father are One,