I'm pretty sure that an East 63rd St branch extension would revive the old stops on University, Dorchester, and Jackson Park/Stony Island. Now sure what CTA's future plans are especially when construction of the Obama Library commences, but I'm hoping that the CTA can't least revive that stub, which many on here all agree should've never been demolished!
I don't believe that extending the Green Line to the South Shore is necessary, since Metra already has a commuter line that travels via 71st St and S Exchange Ave (
https://www.google.com/maps/place/So...l=en&entry=ttu).
I'd also like to see the CTA revive stations along the Englewood branch at Racine and State, just to increase coverage as well as to serve the bus lines nearby. There should be another thread in the Chicago transportation page dedicated about reviving these future stops!