Riot screw up Yuumi real bad. Now Shes both useless and totally afk tier, there used to be an encouragement to go out and get shield for your partner, now you can just stay in and Q forever, then come the best friend effect, if your adc dc you are done for, instead of more fluid gameplay Yuumi got locked up even further.
I've just started and while I do feel like I'm a Minecraft wolf on auto pilot, I've found with certain champions and with the right items she essentially super buffs them and makes it so they can play much more aggressive than normal and at the end, they'll do 55-75k+ damage. I do feel self conscious playing her just waiting for my next spell to come up at times tho