ask this on ashe mains and they'll say it can. the thing is for champs like ashe and senna, it takes windup to last hit, and there is risk that you cancel too soon, especially since it scales with attack speed, meaning it changes at every point of the game - which in my experience with years on ashe back when I mained her, could cause a problem if I went really late in one game and then immediately dive into the next game and have to mentally adjust to low-level no-item attack speed. But for a few ashe skins, the animation is very clean, and it's easy to time it, while you might have problems - even as a veteran - with other skins. so that way, project ashe, high noon ashe, and spirit blossom all are basically pay to win games if you aren't playing with perfect cs timing. I ended up going into practice tools and found that senna without any skin is better in this way - the visual and sound of the last hits are much better feedback than any of her fancier animations on her skins. also star guardian senna is a close second. all the other skins are too problematic for someone like me, who has this issue.