I've been thinking that this "Extended Edition" phenomenon might turn into a business model. It would allow a "theater-friendly" version for initial release of a film, and let its DVD release get back a bunch of footage that was left out, but is ultimately satisfying. I know I've seen several films with their "deleted scenes" placed back in (chief among these are Aliens and Terminator 2. The Abyss, as well, benefits GREATLY from its "recovered" footage) and NONE were anything but improved by its inclusion.
Since a large part of a film's ultimate profit comes from its DVD/VHS/home video sales and rentals, this would seem to be a sure thing for the studios.
Apparently, even Steven Spielberg agrees, as he included both his "director's cut" AND his "theatrical release" in both his release of the E.T. The Extraterrestrial DVD and also for that of Close Encounters Of The Third Kind.
Perhaps, though there's a certain likelihood that it could cut into movie ticket revenues, and a risk that people could become jaded from buying multiple DVD's.
Also, even with a decent home theater system, the movie is going to lose something in the big-screen to small-screen transition. How much would it cost to have a few 'big event' showings of the longer versions of the films?