there are 6 pages or replys, don't have much time to read it all, so i'll just say what i think about this matter.
when u declare a war u get some points (lets say 100) when the first gang who comes to that amount of killing gets some percentage of the other gangs respect, or some percentage of its own gang but from the other gang (e.g. gang A has 100 respect and gang B has 200 respect. A wins and gets 10% of B's respect = 20 respect (A=120, B=180) | or if A wins, A gets 10% of its on but from the other gang (A=110, B=190). but offcourse people like to surrender, some some fewer percentage from the gang who surrenders.
This way it will be much harder for a gang to die. It would be even better if a gang could be in a limited amount of gang wars at the same time 8)