Clan wars: Something to fight for
Clan XP & Perks are the reward for taking part to a war. The winner gains a little more XP, but anyway both winner and loser gain XP. In other words Clan XP can’t ever be lost, soon or later every clan will reach the tenth perk. If you continue to fight your clan could reach also level 11, 12, 13, ... and straight on to the infinite (with no further perks)!
Where is the meaning of this? It misses something to fight for.
If the Clan who lost the war lost also XP points, the Level of a Clan would really be representative of its war ability and the related Perks would be that thing to fight for. That is to say that the Clan Level, or, similarly, the XP amount, becomes a ranking where clans of similar strength occupy close positions and if your Clan wants to climb the ladder it has to improve its war ability.