I love having Yuumi support tbh. She is adorable and it means I never get separated from the support.
The champ is horribly designed and pure cancer. She's broken, not op, not up, just straight up broken. Half the time she utterly useless, the other half horribly op. The problem is neither she, nor the players she's playing against, decide which side of the toxic coin she gets. If some OP carry on the other team (probably in a completely other lane) gets fed then GG and now you have River or Darius or whatever 2v5ing the entire and completely uncounterable. And of course if no one gets fed then by lvl 12 you can forget she exists and its now a 4v5.
She is the epitome of everything wrong with League wrapped up.
Ffs just decide already lol
Yuumi is a gift and a curse at the same time, either she pplies the right lane pressure and you do well with her as your supp, or she's poor at it and it's 1v2 with extra 'summoner spells'
I think Yuumi is very reliable on the team comp and how they benefit having her in the team.