Not going to comment on anything else, but her ONLY weakness?
Jinx is one of the least mobile adcs (you know, when she hasn't just gotten a kill). She's one of, if not the, easiest ADCs to gank in the game (because Kog'maw and Varus won't be pushing the wave in, they'll be farming from long range). Her W has a huge indicator that's easy to dodge, her E takes long enough to arm that most junglers/mids can get past it before it does. She naturally pushes waves as the only way for her to get an edge in lane is to push you to tower. So she's always available to be ganked and is really susceptible to ganks.
That's a huge weakness...
Laning phase has two components. Winning trades and out-cs'ing in the 2v2 scenario - which Jinx excels at. And then surviving ganks and playing well in the 2v3 and 3v2 scenarios - where Jinx is one of the weakest ADCs (well, when she's getting ganked she's really weak. When her jungler is ganking if they land CC she can occasionally chain her E in to it which is pretty strong).
Compare her to say, Tristana (who I think is the most comparable strength-wise).
Both have large AS steroids on their Q which is great for rapidly taking down turrets and other objectives, and also makes them hyper-carries.
Both have sources of AOE damage (Jinx Q, Tristana E and E passive).
Tristana has self peel in the form of her huge knock-back targeted ult which is incredibly reliable, whereas Jinx has her unreliable W and E that can be avoided pretty easily. Tristana wins trades in lane more easily (if she gets her E on you, she wins the trade). Both have a reset that lets them clean up fights.
Now, Jinx has a global ult for sniping kills. Pretty cool and fun to use, but all-around avoidable if you pay attention and have decent ward coverage. That said, still really strong - advantage Jinx.
Tristana has her W to jump away from ganks, jump in on allied ganks, land a slow on enemies. Jinx can chain her E in to CC if her allied jungler/support manages to land it - advantage tristana.
I'd argue Jinx vs Tristana is really balanced. Like about as even as could be. Maybe Jinx slightly stronger because a knockup can interrupt Tristana's W which really sucks for her. Otherwise though, they're even in almost all concepts and what Tristana gains in safety and chase via her W, Jinx gains via chase in her passive and the sniping of her ultimate.
Overall, I think Jinx is mostly fine. There are other ADCs I'd like to see buffs on for sure, but I think overall ADCs are in a pretty weak state right now so I'd want to reserve nerfs for only severe cirucmstances (I mean, they're supposed to be the carries, so why does it seem like the Top laners are carrying every match at worlds...).
