The recent changes to Yuumi have really hurt her. I understand that she is not the most liked Champ, and promoting a passive play style isn't exactly fun, but how have the recent changes moved toward accomplishing this? The worst offender is the W "Channel Time" when re-attaching. It actively promotes NOT detaching, as having to hop back on feels awful. Also, if she detaches and gets hit with some CC (even a silence!) she just floats around uselessly.
Her E being a single charge means you just want to stay on the ADC all the time and give them buff, the Q time reduction just means you have to go for the quick shot, rarely will you pull off anything cool with it anymore, like hopping between 2 Champs to carry the Q further.
I really hope the balance team can take another pass at her soon, because as it stands, she is one of the most clunky and useless champs in the game now.