Tristana's voice. It sounds a little too...Poppy-ish? Or for the lack of a better word, butch?
https://www.youtube.com/watch?x-yt-cl=84503534&x-yt-ts=1421914688&v=mamnlBEUU0E
While I don't think she should sound like
, at the very least I think the pitch should just be a little higher. Not to the extent of
, but "smaller" sounding than what we currently have. You know how in many games when a champion is shrunken, their voice sounds a little more high pitched? I think there should be a hint of that in her voice. She is still a Yordle afterall.
The voice sounds great for 
edit: Shit, this is supposed to be in Story and Art boards, what's it doing here all the sudden?!