I would tier it. Weekend wars cost 2 xstals. If you win one war, you get 1 xstal. Weekday wars cost 1 xstal: Win 2 wars in a row and you get 1 xstal.
Every clan requests xtals, if you don't spend money(can't) or maxed all quests, i believe it should give 1xtal, so at least you can do another war without clan farm.
I support this. KaW is becoming more and more of a pay to win game, and having an extra regen means practically the entire war when the war is one hour long. If devs gave a reliable incentive to continue warring, I think it would also increase turnout. To the people saying that it already gives enough benefits: if that were true, would the number of clans that participate in EE be so small that I can count them on my freaking hand? More incentive to war leads to more signed up clans. More signed up clans leads to better matches and fewer no matches. Think before you mindlessly shoot down a solid idea please.