What I've see thus far looks rather "derivative", what I read so far (admittedly a lot of speculation) about the plot premise sounds original.
My biggest concern had been and still is whether Abrams took Yoda's advice to heart: "Wars don't make one great"
There is a certain amount of expectation for "prequel compensation" among fans and I'm really not sure if Abrams can really provide this.
IMHO, "prequel compensation" has already been accomplished by Dave Filoni and his team with Clone Wars and Rebels.
In case TFA is awful, I'll just paraphrase Humphrey Bogart from Casablanca: We'll always have Bespin