The least i expect of the movie is it does not suck, is not a 2 hour toy or video game commercial. Has character's the audience relates to and sympathize with as protagonists, like the original trio of Mark, Carrie and Harrison. In fact they should get at least Mark Hamill to bridge the trilogies.
If its going to be a bad acting, bad script, cgi fest bore, like the prequels or kingdom of the crystal skull i would not blame any of the original cast for staying clear of that crap.
Anyhow i just cannot see them not messing it up one way or another as fans already have the dark empire comic and Zahn trilogy in their heads, so anything Lucasfilm/ Disney does will be seen as wrong.