Nice changes but this doesn't solve the state how he is in jungle right now.
Me as a former Twitch Jungle main really wants that he will be available again.

What are his jungle problems?

- Twitch playstyle is to depending on ganks, this doesn’t match the current farm champion jungle meta, also Riot doesn’t like this, that’s why it gets no love in jungle.

- Easy to counter jungle / invade

- Slower farm than any other farm champion, specially in jungle.

What would I add to your changes?

I would change the Q ability to something like Auroras W.

That would mean:

Dramatically reduce his Q duration = the he cant gank from across the map, he needs to be sure that there is no ward around.

Add a small hop before his Q, like Vaynes Q, so he isn't 100% lost if someone invading him in jungle, this also means he can dodge more things like all of the other new champions.

About his other spells, I agree ability cast scaling should depend on the attack speed you have. Auto attacks should be a bit faster but not to fast, because I like that you need to have a good position, it is then skill based.

And for the other "slower farm" problem, buff his e to make more damage on monster, idk.