Some random thoughts, some extending on what I said above and some in response to what others said above:
- By appealing to kids and adults I should clarify that I meant to the 6-12 crowd and the 20s-30s crowd, not something that spread from mid-teens to mid-20s. Basically I meant a line that has stuff that I want for me and that my kid would also want (and that I would want to buy for my kid).
-Sets really suffer, IMO, when they essentially recreate a very specific scene from a movie. They're much better when they establish a major place or vehicle that you can then use your imagination and either revisit portions of a movie or create your own stories.
-On the Indiana Jones line, I think it really suffers from the lack of real "must-have" characters beyond Indy himself. Before discussion on LEGO boards driven by the upcoming sets, the only other name I could come up with was Short Round, otherwise it was "Indy's dad", "that other professor", "the Nazi". Contrast with Star Wars, where "must-haves" were at a minimum Luke, Leia, Han, Chewie, Darth Vader, a Stormie, R2, C3PO, and Yoda, followed closely by some more minor but still highly desired ones like a Jawa, Admiral Ackbar, Greedo, Lando, etc. Note that none of the Indy sets stands on its own based on other characters; they all have Indy. Sure, a lot of the OT SW sets had Luke, but there were a bunch based around other figs. I'm not sure what will drive sales of IJ sets to non-AFOLs once they get an Indy, unless they go heavy military.
-I don't know that I agree that SW is successful because it's an army builder. This theme was a hit from the start, even though you couldn't get a Stormy for two years. And then you could only get one Stormy in a TIE set, so it was hard to build up a squad. That's why you would see armies of Scout Troopers, because they came in those little 3-fig packs, but there weren't all that many real army builders back then.
-Just musing on other potential themes that have multi-decade appeal.
-There are the various sports franchises (NBA, Futball/Soccer, potential others like baseball and American football), but since all of the action takes place on a flat surface, there's not a lot of build potential (at least I for one wasn't overly thrilled by sets like "small grandstand with lights").
-Sesame Street? No real adult appeal aside from nostalgia. Perhaps a good Duplo theme that parents would buy for their kids.
-Disney? I don't know how successful the Mickey (Creator?) or Winnie the Pooh (Duplo) lines were. Since they're gone now without having produced many sets I suspect not so much. Potential for some of the classic Disney animated movies, which would have good girl appeal for movies like Cinderella, Snow White, Sleeping Beauty. If at fig-scale (rather than Belville or Scala) you'd get cross-appeal to us castle folk (dwarves, castles, talking mice, okay, scratch that last (oh, Reepicheep and Redwall I suppose)).
-Various other sci-fi potential themes are probably scratched due to the SW license. Star Trek is the big obvious one, but maybe the opportunity has gone by on that since it's been out of the limelight for few years. Others like Battlestar Gallactica, Bab 5, Dr. Who etc seem a little too niche for broad appeal.
-Movie monsters was a potentially great theme but they never really ran with it. Those weren't really licenses, though.
-One of the big problems with movie-driven themes is that, at least in the US, things these days seem very geared towards the opening weekend, and they drop off almost immediately after. It's like hype hype hype nothing. (I blame Will Smith, btw.) I'm trying to think what movies have sort of entered the popular lexicon with staying power after their release. Titanic and the Matrix I suppose, but those have issues as themes.
-There are the various comic-book movies that tap into existing cultural memes, and I do think there is more potential there. I see the point about vehicle driven vs character driven, but I could imagine a great line for Marvel Comics, for instance, that was built around a modular city - not quite at the scale of the Cafe Corner but well built buildings nonetheless that wouldn't look horribly out of place next to the CC, even facades if they were very detailed - and then in each set you get a hero and a villain, with an occasional vehicle set thrown in.