Scriptcs will be continuing. csi is meant to be a bare bones out of the box solution with minimal dependencies. As far as we understand it will also not be extensible.
Our plan is will be continuing down the path we started. We will be re-platting on top of core CLR and new Roslyn scripting bits. We will continue investing fully in our REPL and command line execution experience. We will also being a exploring adding some of the scriptcs capabilities within the Roslyn interactive.