wow, are you really that Jaded? No offense but there must be no joy or happiness left in your life.
I could try to go and make a long winded post about why District 9 is so good, but really, I'm not in the mood to and doing so would kill all the joy that the movie brings me. So I'll say this, I loved D9 for the same reason I loved aliens; Because both are first and foremost action movies, but they're action movies that don't treat the audience like morons. While the pots not super deep but it's a solid, enjoyable story with compelling characters and plenty of on screen excitement.
It may not be the most thought provoking film ever, but it was fun while still being intelligent and I'd actually enjoy watching it again, and that's what makes a movie good.