One of my current favorite blogs, cityofsound, discusses criticisms that Scorcese spent so much effort crafting a beautifully ornate environment to set the Gangs of New York in that he neglected to build a coherent narrative to inhabit it: cityofsound/blog/Gangs Of New York, World-Building. I haven't seen the movie, so I won't comment on that specific claim, although I've heard similar sentiments from other sources.

There is most definitely a general expectation that movies have strong, coherent narrative, especially for blockbusters as opposed to indie flicks. I wonder, though, if movies will begin to echo the trends we're seeing elsewhere moving from directed, goal-oriented entertainment towards open-ended, experiential entertainment? Think of the popularity of games such as SimCity or any of the MMORPGs (Massively Multi-player Online Role-Playing Games), which are primarily oriented around the experience of playing rather than a clearly-defined goal or victory. The incredibly social nature of humans has crept into our games (so much so that for some it becomes a substitute for "real life"; see a first person account of gaming addiction), and I wonder if it will begin to make inroads in other forms of entertainment as well.