Zoe's damage hasn't been nerfed yet because high burst damage is something she is meant to do, and statistically she is not actually that strong. I can agree that she feels overloaded and terrible to play against, but that not should be an excuse to nerf a champion in the wrong place. In this case, if you want to nerf her damage, you are either going to have to rework her, or look for other avenues to buff her, and I don't think stuff like lower cooldowns or even longer ranges would make people happy either. Comparing Zoe's burst to Bard's makes absolutely no sense to me, because Bard isn't designed to be a burst champion, and has a ton of unique utility on the side that Zoe cannot access. Similarly, TF has access to many tools Zoe doesn't have, including global vision and semi-global mobility, and even then still deals most of his damage in a single autoattack (which, unlike Zoe's Q, cannot miss at all). Additionally, both champions are more successful than Zoe: Zoe has a 10% pick rate and 48% win rate, whereas Bard has a 6% pick rate and a 50.5% win rate, and TF a 8% pick rate and a 51% win rate. Zoe's problem is not that she is overpowered, it's that she's poorly-designed, and if you want that to change, you're better off asking for a rework, rather than balance changes.