I haven't followed EU since the late 90s. I barely followed it, then. Just a few books, some comics, and a couple games. So, I can't add much to this debate.
However, I'm guessing that the new trilogy will be a springboard for a sort of revamped, or rebooted, EU. Maybe some PT/OT characters show up in cameos or get brief mentions, but this seems like it's going to be relaunching an entire new slate of characters for the saga. A new universe within the universe.
I think Lucas wants to ensure that, while he's handing off the creative steering wheel to others, all the new content fits in with what he'd envision. The past EU stuff doesn't get thrown out, but I think it's going to be like the Star Trek film reboot. I'm not saying it's going to be an alternate universe. I just think that there won't be too much crossover, if any, between EU stuff before ~2015, and EU stuff after ~2015.
Not sure if it makes sense what I'm trying to convey.