Season 2 isn't the best, but it's a really good season. It shows not only how the upper echelons of criminals never get caught, but also how the economy is the biggest indicator of whether people turn to crime. Watching dock workers who could once support an entire family, slowly erode until they can't even afford car payments unless they ship drugs? It's an essential part of the story. Every facet fits together to show how crime isn't something inherently bad people do--it's something that happens when inequality has reached levels where people start to lose hope. When someone feels like they have nothing to lose, societies control fades.
That's why The Wire is great...It's the story about the slowDeathof a City.