Qhira is quite powerful, and I expect her to receive some nerfs coming soon, but until then, there are some strategies to counter her. I would suggest checking out this thread for a fuller discussion on the topic: Where's the counter play?
As for her nerfs, I think nerfing her healing on her tier 3, removing the microstun from her initial impact of her E, and possibly increasing her rotation speed of her swing (making its use harder in some scenarios and the invulnerability time less) would do leagues to getting her in a more balanced position, without entirely destroying the character. If she still is overwhelming, we could see a minor nerf to some of her extremely popular bleed talents or her bleed damage baseline.