I feel she is way too weak early game. Not even a threat really. There are champions who are good late game, but they are ok mid game. Tristana is only very good late and that is only if you are very fed. Also the majority of games won't go to 50 minutes long. That's where tristana is even slightly viable.
She's viable, it's just really REALLY painfull to win a game as her.
You don't know what I had to do to get level 7 Tristana...
Trist her lategame has actually been nerfed. Ever since her rework the buffed up her early & midgame. I think it's a verry risky to buff her since she can become one of the strongest champions in no time with all of those jump resets. She don't seem to work verry well with the new korean builds so that's probally the reason she isn't top tier right now. She's still viable, their are just other champions that can currently match her in strength on the things she can do
she's fine, their will be a fine she will be OP again. It's just because where in a utility based marksmen meta right now with champions like 
