Been playing her kit on the PBE, albeit I can't take it to live games at this point except Blitz.
She's definitely a support, and I see her as a bit of a counter to hook champs. Her W is useful for faking engages, faking fake engages that turn into engages, intercepting hooks and countering the zoning those champs have on open areas, intercepting hooks on behalf of your ADC (though that might take a lot more effort to make happen). I could even see it doing things like intercepting Jhin ults and related.
Her poke is pretty good, but I expect that to be massively nerfed by the time the new season hits. It's just super potent, especially with a well-executed EQ combo. Then add a 3rd AA off the W passive, and yeah. Probably not going to be as potent as a damage dealer as she is right now.
There's a lot of opportunity to fake people out with her W, but I don't know that it will work as much as one might like. A lot of vision countering will need to happen and shifting smart. But popping a W while disguised as your ADC seems legit.
Her R seems hit or miss. At least as far as a supp kit would go. She will have a hard time closing gaps to land it, and she puts herself in a lot of danger being that pushed in a 2v lane. IDK though, I'm not that good and I haven't seen her much in action on a normal Rift game.
Where I think she will also be strong is in her vision warding. The W gives a speed boost and can be used to fake out her actual location to some degree while she tries to deep ward. Pair that with a EQ if she gets caught out, and she has a good chance of avoiding engages or doing enough damage to make a pursuit seem like a bad idea.
I don't see her as a good jg. I think the W is wasted potential for a jg, and her solo power seems item dependent. At level 6 with some items and at least a red buff, she can definitely clear camps, and I think that might give her a chance to do some counter jungling. She can solo dragon, too, but it's very weak and risky early game.
But I am sure someone will get good use out of her as a jg and make that a meta. Definitely don't think her kit was designed for it, but I could be wrong.