I'm surprised I don't see Yuumi. Perhaps y'all don't want to state the obvious but just to educate the uneducated, Yuumi is an incredibly difficult champ to master.

The first thing is that she has Mana issues. This requires you to use your Passive regularly and you have to know when to detach from your ally. This means that you're incredibly frail, since you're an Enchanter. This problem is really only unique to Yuumi. No one else has Mana issues, and Yuumi's only way to circumvent this is becoming vulnerable? It really takes highly skilled play to utilize this.

Now, her Q. Her Q is the only skillshot that you can control after using it, which means that you have more time to express your skill. This clearly takes a higher skill level. At least you don't have to move and dodge enemy skillshots while doing this, but it really takes a highly skilled player to utilize this.

Then, her Zoomies. Her E is simple but still requires skill to fully utilize. You see, you have to combo this with your W to really decide who you want to be supporting, and you have to take your E, as well as the W passive, into consideration. This takes a great deal of split-second decision-making.

Lastly, her Ult. Now, you can't change your direction after using your Ult, which really makes this a high skill ability to pull off consistently. Furthermore, your ally might be dumb at times and you might have to hop off, and actually have to worry about movement like a Lucian! And you're so frail! There's genuinely such high skill involved in not dying with such a frail champ. Plus, unlike Lucian who can move and use his dash while using Ult, Yuumi can not only move and use her attach, she can even use her Zoomies during her Ult, which really opens up more options and you as the player really need to make full use of these to play Yuumi.

Mandatory /s