So... how about 50-100 exp toward clan perks if the clan gets max stars? A little incentive and a little goal mixed into one. The way people attack would be different as well.
Interesting twist and possibly perks a little faster?
Getting 100% of the stars rarely happens, if you make high level war, where it is hard to even get 2 stars sometimes, it would be impossible.
I think the 60% bonus is to balance this. 60% is very easy to obtain in low level clan wars. But in townhall 10 exclusive wars, 60% is not that easy anymore. 100% would be impossible.