Simple yet effective Illaoi buff for your consideration
I think we all know the Illaoi is in a bad spot, She can do ridiculous amounts of damage yet lacks anything fun or compelling about her kit. She is also extremely easy to play around.
So a simple buff would be to give her W a 20% slow when it lands on an enemy but if the champion is a vessel it gives a .75 second root, maybe add an animation of a tentacle coming out of the ground and wrapping around the champion effected. It would give her a little bit more consistency and a cool combo system with her vessel mechanic which to be honest can be nothing more than a gimmick if the player is paying attention.