Heheh, Meet Joe Black. I do think there was a fair bit of padding in Avatar that could have been trimmed down to allow time for more character stuff (really, when a film is three hours long, I expect it to show a little complexity), but you could be right about the special effects sequences being more satisfying to the average audience member. :|

I am not at all against happy endings. I don't think it hurts us to have sad endings now and then, but a lot of the time when filmmakers end a movie on a downer note, they're doing it solely for the sake of not following the happy ending tradition. And that's not a good reason at all.