"Stay A While And Listen" would be a hilarious and effective ultimate to add to League
Since Riot's added in the Sleep CC, there's no reason to only let Zoe have it.
In HotS, Deckard Cain gets to put an entire team to sleep with his ultimate if he lands it right, something I find both hilarious and powerful. Of course, it's not as broken as it sounds, as he can be interrupted, and there are many ways of making yourself immune to CC in HotS.
If we got an "old wise scholar" as a Champion eventually (excluding Ryze), would this ultimate be allowable in the game? Or does it tread too much on Sona's niche?