By winning a war, your clan either takes "War Points" from the other clan or receives them. War points can be spent on upgrades, (One idea for example is a __ hour shield for the whole clan to use when they want or when the leader chooses and will be added on to any shields already active)
By winning a war, the top players of the war, or everyone who participated in the war should receive a sum of gems. It doesn't have to be a lot, but enough where it is worth it.