The only new character I like is Drew. A former med student who comes back to get back on top of things. From what I've seen, he should've been the POV character.
Lucy is, as others have said, JD 2.0. The creators are playing it very safe by not having a truly new main character, which to me is a big problem. And her voice-over work is awful. I'm with a few other people in saying that she is trying way to hard to fill Braff's shoes. It's not working for me.
I enjoyed these first two episodes, but outside of Drew's interractions with Dr. Cox, all the laughs came from the old cast. Once they're gone, I don't see this going well. But well just have to find out.