Her kit is fine IMO. Maybe even a tad bit OP.
1) She is an AD carry with an AOE blind, a slow, and low CD steroid. This means that she could potentially destroy a lane against another ADC.
2) It seems to prioritize low health minons and Champions, I haven't had a problem with it. You can also refresh it with her E, giving her a ridiculous amount of burst.
3) That steroid scales nicely late game with items, and again you can spam it with E.
4) Bots can even CC her E, not sure if its even possible. Think of it like Caits E by its not a skill shot and a bit more reliable.
5) Her the melee part of her ult is either for clean up or escaping, the true power of her ult comes from the second cast. Its like Garens ult (does more damage to people low health) but AOE.