Riot Games developer David "Phreak" Turley explained Yuumi nerfs in a recent video about AD Carry adjustments of patch 13.1b. He revealed that the champion was rebalanced to "remove her from professional play" and, at the same time, boost her popularity in solo queue.
Yuumi's changes were met with backlash, and that's why Phreak decided to defend the nerfs. He claims "low-key, she's not really that much worse" for solo queue. The problem is professional games where her skill kit was used to perfection, making games boring. At the same time, Yuumi's pick rate might grow up because of fewer bans.
I am pretty confident Yuumi should be gone from pro play. These are too much of a laning phase nerf to be playable in pro play. And pro will look better as a result.
Patch 13.1b came out on January 24, replacing 13.2 following a cyber attack on the development environment in Riot Games. The Yuumi was hit with several nerfs from base stats to her passive, W, and E.
Passive: Bop ‘N’ Block
W: You and Me!