In ARAM she can not use her ice element, as there is no river to gather the element from.
Did you even think of the other modes when you designed this champion ?
She is also rather bad, as in she is squishy like Yi but has no ability to counter this, I mean she has a tiny dash, a very hard to use ulti and is very squishy.
She isn't the trickster champion you made her out to be, rather disapointing actually.
Her stealth is in a tiny area, well within enemy attack range, her slow and execute are usless except as KS abilities not teamfights, and her dash wont save her from a drunken Annie, its too tiny and circumstantial.
All in all she is a poor version of Yi without the ability to murder noobs... at least in ARAM and I cant really see her doing well in SR or pro play.
In a positive note I do like how Riot are experimenting but this blew up in the dongers face tbh.