Tristana needs a new passive
Exactly what the title says, I don't think nerfing her damage was the way to nerf her as it did nothing. What makes her good is that she can poke really well with her high range thanks to the passive with the combination of these items
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That at max rank would deal: Crtical strike damage + 280 from Rapid Cannon & Statik shiv
Giving Triatana a new passive would be the right step in my opinion.