I like the utility hyper marksman aspect to her, but no one is going to play her as a support, too much potential on the table with Runaan's Hurricane, Essence Reaver, Stormrazor, etc. which is fine because she fits the same space as Ashe, but with different levels of utility.
Also, she just does not have a very good support kit at all, she just has a kit that can aid her team like an Ashe or Kalista can do (which Kalista can be done a lot better at this by removing her stupid unique sword item and allow her to interact with every member of her team like normal team-based abilities work).
- Remove the movement speed on her passive. This is not needed and is just adding to both mobility creep problem and over tuning this kit. She has a heal, root, and untargetable spell for her defense, she does not need anymore than this, not to mention she is a long range marksman. Plus she gains some movement speed from her E already and she can always go Fleet Footwork for attack movement speed anyways.
- Percentile damage naturally scales, so it does not need two scaling aspects. Give this a static damage value of like 8% current health or something, it will naturally be weak early on and naturally be strong late game, or given her attack speed is so damn low it could be a higher value than this.
- Buff up her ability power ratios, they are too low, like way too low and can be increased by a lot.
Her attack animation feels so freaking good to use, great job!
Overall remove the unneeded fluff on her kit, like her passive movement speed, to not have her be crazy strong once she hits live servers.