I've seen a lot of people suggesting already existing characters/events/concepts/whatnot as being a larger feature of the ST. I have to say I completely disagree with this. While I do understand someone's wish to see their favorite EU, TCW or PT thing appear in ST in a larger role - there is no need to recycle already used and seen content. I find it highly implausible that anything from any existing material will feature in ST as anything larger than a few second cameo for fans to enjoy. There is simply no need to waste an opportunity to create something new and fresh in Star Wars by adapting or reusing existing stuff. At least, in these first movies. Later on, who knows, but now I simply don't see it as happening.