With 8.6, i've been able to make my 40% win rate with her into 50% since her release (needed a lot of games to close that gap). When she goes even in lane, she relies just as heavily on her team as anybody else and can't safely dive anybody she feels like, but when she starts snowballing, her assassin role really shines and you can start nuking people. From there on, as long as you can make your picks, carrying a lead is easier than ever. The part that feels fair though is that she has such long cooldowns that she can be punished during unless you have a massive lead by then and can just beat someone with your passive and wait for another Q to come off CD in time. My favourite part is that you can get a Q upgrade by level 8 with an ER and Pickaxe (99 AD @lvl7). If there were to be any nerfs, I think just lowering the damage on her Q by 5 per missile would suffice. Otherwise, her raw stats seem fine in comparison to other ADC's. Her AD growth is negligible as well as her base AS and AS growth. Too much tuning and she might go from playable back to 40% town.
Damage per missile: 45 / 61.25 / 77.5 / 93.75 / 110 (+40% bonus) (+40%) to -----> Damage per missile: 40 / 56.25 / 72.5 / 88.75 / 105 (+40% bonus) (+40%)