I watched the extras on the DVD and they talked about some of the changes they made in the script. I found it really interesting that they had planned on Cochise and Vermin being killed and Swan kidnapped. It really would have added a sense of doom for the Warriors. As they clash with different gangs, they are slowly losing numbers. And I think it would have made the confrontation with the Rogues even stronger. Here were these 4 survivors (4 dead, 1 arrested) and just when they think it's over, here's one last battle.
While the movie was set in a future time and based on a Greek story, I think those changes would have added a message of futility and senseless to being in a gang. Not a heavy handed "stay away from gangs" message, but a conclusion that the viewer would interpret on his own.