User blog comment:JmLyan/Arana, the Lotus Archer/@comment-24526576-20140214202716/@comment-24526576-20140216002120

But you cannot use the attack button for an ability. If Mystical Focus is meant to be channeled and you have to stand still for it, you can add that to the ability like Teemo's Innate.

And you're right, not all champions have their spamable damaging ability on Q, but most of them do. And when you think about it, a good Ashe player should use the Q button more in fights then the W button.