Poppy was a little overnerfed
I think that the last set of nerfs to Poppy went a little too far. Her win rate is now solidly under 50%. She doesn't have the tools to dominate top, but doesn't scale into late game like the other tops who struggle in lane. She has solid utility in teamfights, but she's clearly not winning games just based on that.
Personally, I think that her passive and autoattacks in general could use the most attention; as others have mentioned it can be very clunky to try to weave in the passive with the normal speed of her autoattack animation.