well, this is fun to look back on!
>>6 got it about right, no attempt at major comedy or even meaningful plot, instead we got the importance of family, some really dodgy lisa subplot and barely any mister burns, who was replaced with some shameless satire involving arnold schwartenegger as president. no attempt to take anything out of the series' comfort zone either; no age difference, no character development, no different points of view, just an hour and a half eopisode of mediocrity. and speaking of slow moments for drama, just wait until your future selves see the movie, because there is not enough room or time to talk about it all.
oh, and it's all environmental. yep.