I don't think social importance necessarily makes for a better movie, but let's think ahead 20 years and look back on traffic and gladiator.
Gladiator will be outdated in terms of the visual effects and be what it is at its core--a thin storyline supporting some wild visual effects. when the effects are dated, the story will seem even thinner. Not that this was a BAD movie by any means, I just didn't think it was all that.
Traffic will hold up to the test of time. Stylisticly, it will be marked as early 21st century. Structurally, the same. Story, the same. But it will still be powerful and not diluted by time as I believe Gladiator will.
when the Academy is looking for best picture-- it is not only looking for the best picture entertainment wise--but what will continue to be the best picture of that particular year? What will stand the test of time and not leave audiences wondering 20 years from now how the 2000 academy could have voted a certian way...
Again, all IMHO.
Amy