Maybe it's just because of the fact that I have the highest mastery score of any champion on Ashe, but, in my opinion, Ashe is the most satisfying ADC when you are the one carrying your team. When you are kicking ass with her, you know that YOU are kicking everyone's ass, and the champion itself is not somewhat carrying you.
This is only amplified by the fact that Ashe doesn't feel bad to play. She's nothing like Jhin, where every auto and ability is so damn satisfying to the point of being orgasmic, but she's also not Kalista, where you honestly feel the hindering mechanics in her kit. There's just enough there to keep you coming back (not to mention, her PROJECT skin makes this all that much better.....everything is just so smooth on that skin).
I've always said that in order to get good with Ashe, you have to learn how to dance with her. Once you're able to do that, you'll have some of the most satisfying wins you could have.