The only thing i find very powerful about her is Zap! the damage is pretty insane, but asides from that, she isn't very special as an ADC.
Since if you change weapons with Fishbones/Pow-Pow the attack speed can't be used for both weapons, the range of Pow-Pow is very short but the attack speed of Fishbones is very low, her traps are pretty good but you can avoid them very easily, and unlike Caitlyn's traps they don't give you vision of the enemy, nor last 4 minutes, and her ult is not as strong as it looks, more often than not Ezreal's Trueshot Barrage or Draven's Whirling Death do a better job securing a kill,
If you are gonna play Jinx... you should probably pick Tristana or Caitlyn, Tristana at level 18 with her Q is pretty much Fishbones/Pow-Pow combined (without the AoE), her escape resets on kills or assist and on top of that she has a knockback.
Caitlyn has Fishbones range at level 1, the traps have more impact and she has a escape & slow, AND a more reliable ult.
This are just my thoughts.