I hope that they don't bring back ghost characters like Yoda and Obi-wan, but for a different reason. Years from now, a whole lot of kids will have seen Episode 7 before any of the other movies, and to ruin Yoda and Obi-wan and spoil Anakin before they've seen the Originals is as bad as what the prequels did. There will come a time when nobody will have experienced Luke's revelations concerning Yoda and Vader as revelations, having been told this information in both the prequels and the sequels. And that does great damage to the Originals in my opinion.