My answer can be found over at EDSBS. I go into detail at the link, but the best way I can sum it up is that offenses are like Tolstoy’s families: good offenses tend to be similar in that they all are coherent, have good line play, and have balance in one sense or another, while crappy offenses, like Tolstoy’s unhappy families, are crappy in their own ways.
Check out the full thing.